A switch cementing fracturing sliding sleeve

Abstract

The present invention relates to the field of oil and gas wells, and discloses a switch cementing fracturing sleeve, including a sleeve part and a switch sleeve tool, wherein the sleeve part includes an outer tube and an inner sleeve arranged in the outer tube, wherein the outer tube is provided with a plurality of sandblasting holes in the circumferential direction, and the inner sleeve can make the sandblasting holes flow after sliding, and the switch sleeve tool includes a center tube, a rubber tube unit sleeved on the center tube, a slip part and a positioning unit, wherein the rubber tube unit can be radially expanded after being sealed to realize an annular space sealing between the inner sleeve, a limit ring is provided on the inner wall of the outer tube along the sliding direction of the inner sleeve, and there is a gap between the limit ring and the initial position of the inner sleeve, and the positioning unit includes a positioner, wherein a convex ring part with circumferential elasticity is provided in the middle of the positioner, and the outer diameter of the convex ring part is larger than the inner diameter of the inner sleeve in the natural state. By operating the switch sleeve tool, a sleeve and a switch tool that can be accurately positioned and easy to operate are provided.

Description

Technical Field

[0001] The invention relates to the field of oil and gas wells, and in particular to a switch cementing fracturing sliding sleeve. Background Art

[0002] Casing and sliding sleeve fracturing technology is a technology that uses a high-pressure pump to inject fracturing liquid into the well wall to enhance the permeability of the formation and improve the production capacity of the oil well. It is widely used in oil field exploration and development, and has the advantages of simple operation and obvious effect. In addition, the multi-stage sliding sleeve segmented fracturing technology of horizontal wells is an important means of unconventional oil and gas resource exploitation, with the characteristics of simple structure and high construction reliability. This fracturing technology is widely used in fracturing and production enhancement of shale gas, low permeability production layers, and thin oil layers. In the later stage of oil and gas well exploitation, if water is produced in the production layer, selective exploitation, and re-fracturing are encountered, it is necessary to lower the sliding sleeve switch string to perform the sliding sleeve switch operation, selectively close the sliding sleeve, and achieve the purpose of plugging bottom water, layered plugging test, and production. When facing the sliding sleeve, traditional opening tools and fracturing packers are often difficult to accurately locate the switch, and the opening of the sliding sleeve and the sealing of the fracturing packer requires multiple string trips, which is more complicated and has a low success rate. Therefore, it is necessary to provide a sliding sleeve and switch tool that can be accurately positioned and easy to operate. Summary of the invention

[0003] The present invention is intended to provide a switch cementing fracturing sliding sleeve, so as to provide a sliding sleeve and a switch tool which can be accurately positioned and conveniently operated.

[0004] To achieve the above-mentioned purpose, the present invention adopts the following technical scheme: a switch cementing fracturing sleeve, comprising a sleeve part and a switch sleeve tool, the sleeve part comprising an outer tube and an inner sleeve arranged in the outer tube, the outer tube is circumferentially provided with a plurality of sandblasting holes, and the sandblasting holes can flow after the inner sleeve slides, the switch sleeve tool comprises a center tube, a rubber tube unit sleeved on the center tube, a slip part and a positioning unit, after the seat is sealed, the rubber tube unit can be radially expanded to realize the annular space sealing between the inner sleeve, the inner wall of the outer tube is provided with a limit ring along the sliding direction of the inner sleeve, and there is a gap between the limit ring and the initial position of the inner sleeve, the positioning unit comprises a positioner, and a convex ring part with circumferential elasticity is provided in the middle of the positioner, and the outer diameter of the convex ring part is larger than the inner diameter of the inner sleeve in the natural state.

[0005] The beneficial effects of this program are:

[0006] The sleeve part in the technical solution is placed in the formation to align with the oil and gas layer. According to the number of oil and gas layers required, a certain number of sleeve parts are connected according to the corresponding position (interval distance). At this time, the inner sleeve blocks the sandblasting hole, so the sleeve part is in a closed state. The inner diameters of multiple sleeve parts are consistent. After they are put in place, cementing is carried out. When the sleeve part needs to be opened, the switch sleeve tool is brought in by the continuous tubing tool and lowered to a predetermined position (generally, it is opened or closed step by step from the deepest level upwards). The switch sleeve tool can be repeatedly sealed and integrated with the inner sleeve to drive the inner sleeve to slide along the outer cylinder. After reaching the predetermined position, the tool string is slowly lifted and lowered. The inner diameter of the normal casing is the same. There is no tonnage load change display when the switch sleeve tool is lowered. In the technical solution, a convex ring part is provided in the middle of the positioner. By setting the position of the convex ring part, the outer diameter of the convex ring part is larger than the inner diameter of the inner sleeve in the natural state. When the tool string is lowered, the convex ring part slides to between the limit ring and the initial position of the inner sleeve. When the tool is in place, the convex ring will pop outwards. By sensing the pop-up and the lifting and lowering forces, it can be judged whether the positioning unit is in place. By lifting and lowering with a certain amount of hanging force, the tonnage load changes caused by the hanging force, it can be judged that the convex ring has been stuck in the set position. After it is judged to be in place, the tool string is lifted up by operating the continuous tubing for a certain distance, and then lowered again for reversal, and the seat seal is completed by continuing to lower. At the same time, the rubber cartridge unit can be radially expanded to achieve the annular seal between the rubber cartridge unit and the inner sleeve, that is, the rubber cartridge unit The element is compressed and stretched under the pressure of the weight load of the pipe string, and the high-pressure fluid is pumped in from the annulus in a large displacement. Under the impetus of the high-pressure flow, a huge thrust is generated, forcing the switch sleeve tool engaged in the inner sleeve to slide downward together with the inner sleeve of the sleeve part to complete the opening of the sleeve part. After the sandblasting hole is opened, the liquid and proppant are pumped into the formation from the annulus through the sandblasting hole in a large displacement on the ground to complete the fracturing. When the sleeve part is opened to complete the fracturing of this section, the tool string is lifted, the seat seal is released, and the rubber cartridge unit is released from the expansion state.

[0007] The cam is then pressed against the stop ring to allow the cam to slide back and forth, and the cam, when in contact with the inner sleeve, is released, and the cam, when in contact with the inner sleeve, is released and the cam is released, the cam is released and the cam is released. The convex ring portion in the embodiment also serves as a friction body in the switch sleeve tool, increasing the friction of the switch sleeve tool sliding in the sleeve portion, helping the switch sleeve tool to better fit the casing wall and automatically center. Through the above-mentioned arrangement, the operator can accurately judge whether the tool is in place through induction and tonnage load changes, avoiding multiple adjustments and trial and error, greatly reducing the risk of operation failure, ensuring the safety of the operation process, and being able to effectively limit the sliding distance of the inner sleeve. When necessary, the inner sleeve can be pushed back by lifting the tool string and the sleeve portion can be closed again, ensuring the controllability of the fracturing operation.

[0008] Preferably, as an improvement, the rubber cartridge unit includes a rubber cartridge, and an upper pressure cap and a lower pressure cap arranged on both sides of the rubber cartridge, the lower pressure cap is close to the cava portion, an upper cone is sleeved on the outer side of the lower pressure cap, and support protection rings are provided at both ends of the rubber cartridge.

[0009] The beneficial effect is that when the switch sleeve tool is sealed, the rubber sleeve can radially expand to seal the annulus.

[0010] Preferably, as an improvement, the cava part includes a cava seat and a plurality of cava and springs circumferentially arranged on the cava seat, the cava is embedded in the cava seat, both ends of the cava are conical surfaces with a certain angle, both ends of the spring are respectively against the middle part of the cava and the cava seat, and also includes a lower cone located inside the positioning sleeve and slidingly sleeved on the center tube, and when the cava is against the lower cone, the cava can expand radially in the cava seat.

[0011] The beneficial effects are as follows: the expansion of the slips provides support for the compression of the rubber cartridge. The design of the slips allows the slips to expand radially after contacting the lower cone, providing strong support to ensure that the rubber cartridge unit can expand smoothly and complete the annular seal between the inner sleeve. Since the design of the slips can withstand the high-pressure fluid and mechanical stress of multiple fracturing operations, the tool has a long service life and can adapt to multiple fracturing operations, reducing the cost of frequent tool replacement. The precise matching of the spring, cone surface, and lower cone of the slips ensures the stability of the tool during operation and reduces possible failures or errors in operation.

[0012] Preferably, as an improvement, a reversing track is provided on the outer surface of the lower section of the central tube, a rotating ring is rotatably provided at the end of the positioner, a track pin is fixed on the rotating ring, and the end of the track pin is inserted into the reversing track and slidably matched therewith.

[0013] Preferably, as an improvement, the reversing track includes a plurality of long track grooves and short track grooves extending along the circumference of the center tube, and a reversing groove connecting the tail ends of the long track grooves and the tail ends of the short track grooves, the length of the long track grooves is greater than the short track grooves, and the long track grooves and the short track grooves are spaced apart along the circumference of the center tube, and also include fixing pins, and the outer tube and the inner tube are circumferentially provided with a plurality of fixing pins for connection.

[0014] The beneficial effects are as follows: the end points of the long track groove and the short track groove away from the reversing groove are dead points, and the end points of the reversing track grooves are the track-changing dead points. When going down into the well, the track pin is at the dead point position on the short track, and there is a friction force between the limiter and the sleeve part. The lower cone does not contact the slip part, and the rubber cylinder unit is in a non-pressurized state, ensuring that the pipe string can be smoothly lowered into the well; when the convex ring reaches the predetermined position (between the gap between the inner sleeve and the limit ring), the pipe string is lifted up and lowered, and the slip and friction block assembly enter the upper dead point of the long track from the short track, and the pipe string is lifted up and lowered, and the upper cone pushes the slip to open, so that it bites on the inner wall of the casing to form a The rubber sleeve is compressed and its diameter increases, thereby isolating the annular space of the oil casing and realizing the packer effect. High-pressure fluid is pumped in from the annulus in large displacement, and a great thrust is generated under the impetus of high-pressure circulation, forcing the continuous tubing + switch sleeve tool engaged in the inner sleeve and the inner sleeve of the switch sleeve to move downward. When the downward thrust reaches the shear force of the inner sleeve fixing pin of the switch sleeve, the fixing pin is cut off, and the inner sleeve is pushed to continue to move downward, completely exposing the sandblasting hole of the switch sleeve, completing the opening work of the switch sleeve. At this time, the sleeve is connected with the formation, completing the circulation of the liquid in the casing and the formation. The above-mentioned setting enables the operator to accurately control the opening and closing of the sleeve, especially in multi-stage fracturing operations, the sleeve part can be opened or closed step by step and in sequence to ensure that the operation of each stage can proceed smoothly, and the positioning and isolation operations are realized through lifting and lowering control, which saves time and manpower and reduces the complexity of the operation. After the inner sleeve descends through high thrust, the fixed pin shears and pushes the inner sleeve to open completely. After the sandblasting holes are exposed, the high-pressure fluid can smoothly enter the formation, effectively improving the fracturing effect of shale gas, low-permeability oil and gas layers, etc., promoting the flow of oil and gas, and increasing production.

[0015] Preferably, as an improvement, it also includes a righting portion, which includes an upper righting portion and a lower righting portion, the upper righting portion is located on the side of the rubber cartridge unit away from the locator, the upper righting portion includes a righting tube and a righting body circumferentially arranged on the righting tube; the lower righting portion includes a tail pipe fixedly arranged on the end side of the locator, the tail pipe is provided with a through hole circumferentially, a guide cone is fixed at the end of the tail pipe, and the guide cone is also provided with righting bodies at intervals circumferentially.

[0016] The beneficial effects are as follows: between the casing couplings, the tool string may get stuck due to being not centered or due to poor guiding, causing interruption of the operation. By providing a straightening portion, through the cooperation of the upper straightening portion and the lower straightening portion, the switch sleeve tool can be kept centered in the casing, and the tool string can be prevented from deviating from the center of the casing during the lowering process. A straightening body is provided on the guide cone at the end of the tail pipe. On the one hand, it keeps the tool string, especially the positioning unit, centered, and reduces the jamming caused by friction or asymmetric force; on the other hand, it facilitates the smooth lowering of the tool string and prevents it from getting stuck between the casing couplings; through the cooperation of the tail pipe of the lower straightening portion and the guide cone, the tool string can remain stable during the lowering process and smoothly reach the predetermined position.

[0017] Preferably, as an improvement, a balancing valve is fixedly connected to the other side of the upper pressure cap, the balancing valve is provided with sealing material, and the balancing valve is sealed with the center tube.

[0018] The beneficial effect is that during the lowering of the switch sleeve tool string, a balancing valve is set to prevent the pressure difference between the upper and lower parts of the pipe string, thereby preventing the packer rubber cylinder from being sealed prematurely due to liquid pressure. The operator can ensure that when the tool string is lowered to the predetermined position, it can be sealed at the appropriate time, avoiding repeated work due to premature sealing at an inappropriate time.

[0019] Preferably, as an improvement, a release joint is further provided between the upper straightening portion and the rubber cylinder unit, the release joint comprising an upper joint, a lower joint, an elastic claw, a sliding sleeve and a plurality of shear pins, the elastic claw is sleeved on the sliding sleeve, the upper end of the elastic claw is clamped with the upper joint through the circumferentially arranged shear pins, and the lower end of the elastic claw is circumferentially sleeved on the sliding sleeve and is expansion-clamped with the inner wall of the lower joint.

[0020] The beneficial effect is as follows: through the above arrangement, if a special situation occurs and the pipe string is stuck, since the tensile load of the continuous tubing is not very high, it cannot be pulled out within the safe load range, and the only way is to forcibly pull it off and release it (the set value is much smaller than the tensile strength of the continuous tubing), that is, use a large pulling force to pull the upper straightening part to break the shear nails through the pulling force, so that the upper joint and the lower joint are separated, and the subsequent tools are lowered for salvage or drilling and grinding; during the continuous tubing operation, the jamming of the tool string may cause the entire operation to be suspended, affecting the operation efficiency. Through the design of the release joint, when jamming occurs, the shear nails can be broken by pulling force, the upper joint and the lower joint can be quickly separated, and the jammed tool string can be released, which can ensure the smooth recovery of the tool string and reduce the downtime when jammed.

[0021] Preferably, as an improvement, it further comprises a sandblaster, the sandblaster has a plurality of openings in the circumference, and the sandblaster is arranged between the balancing valve and the release joint.

[0022] The beneficial effects are as follows: the sandblaster is used to provide liquid and proppant during the fracturing process. The sandblaster has multiple openings around it so that the liquid and proppant can flow out from the sleeve during the fracturing process and enter the formation channel. The expansion of the rubber tube is mainly driven by pressure, so that the fracturing fluid and proppant (solids such as fracturing sand) can flow out from the annulus into the formation.

[0023] Preferably, as an improvement, the positioner is provided with a plurality of transverse openings in the circumference.

[0024] The beneficial effect is that the convex ring portion has radial tension elasticity. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a structural schematic diagram of an embodiment of the present invention;

[0026] Figure 2 A partial cross-sectional view of an embodiment of the present invention;

[0027] Figure 3 This is a schematic structural diagram of a hand-release joint according to an embodiment of the present invention;

[0028] Figure 4 This is a schematic diagram of the commutation track structure according to an embodiment of the present invention;

[0029] Figure 5 It is a schematic diagram of the structure of a rotating ring according to an embodiment of the present invention. DETAILED DESCRIPTION

[0030] The following is further described in detail through specific implementation methods:

[0031] The figure marks in the drawings of the specification include: outer cylinder 1, inner sleeve 2, sandblasting hole 3, center tube 4, limit ring 5, locator 6, convex ring part 7, transverse opening 8, rubber cylinder 9, upper pressure cap 10, lower pressure cap 11, upper cone 12, slip seat 13, slip 14, spring 15, lower cone 16, rotating ring 17, track pin 18, long track groove 19, short track groove 20, reversing groove 21, straightening tube 22, straightening body 23, tail pipe 24, guide cone 25, balancing valve 26, upper joint 27, lower joint 28, elastic claw 29, sleeve 30, shear pin 31, sandblaster 32, support and protection ring 33.

[0032] Example

[0033] The embodiment is basically as follows Figure 1-Figure 5 As shown, Figure 1 and Figure 2A switch well cementing fracturing sleeve 30 is shown, comprising a sleeve part and a switch sleeve 30 tool, wherein the sleeve part comprises an outer tube 1 and an inner sleeve 2 arranged in the outer tube 1, wherein the outer tube 1 is provided with a plurality of sandblasting holes 3 in the circumferential direction, and the inner sleeve 2 can make the sandblasting holes 3 flow after sliding, and further comprises fixing pins, wherein the outer tube 1 and the inner tube are provided with a plurality of fixing pins in the circumferential direction for connection. The switch sleeve 30 tool comprises a central tube 4, a rubber tube unit sleeved on the central tube 4, a slip part and a positioning unit, wherein the rubber tube unit can be radially expanded after sealing to realize annular sealing between the inner sleeve 2, a limiting ring 5 is provided on the inner wall of the outer tube 1 along the sliding direction of the inner sleeve 2, and there is a gap between the limiting ring 5 and the initial position of the inner sleeve 2, and the positioning unit comprises a positioner 6, wherein a convex ring part 7 with circumferential elasticity is provided in the middle of the positioner 6, and the length of the gap is greater than the length of the convex ring part 7, and in this embodiment, the length of the gap is equal to the length of the convex ring part 7, and the outer diameter of the convex ring part 7 is greater than the inner diameter of the inner sleeve 2 in the natural state. The positioner 6 has a plurality of transverse openings 8 formed around its circumference.

[0034] The sleeve part in the technical solution is placed in the formation to align with the oil and gas layer. According to the number of oil and gas layers, a certain number of sleeve parts are connected at the corresponding position (interval distance). At this time, the inner sleeve 2 blocks the sandblasting hole 3, so the sleeve part is in a closed state. The inner diameters of multiple sleeve parts are kept consistent. After they are put in place, cementing is carried out. When it is necessary to open the sleeve part, the switch sleeve 30 tool is brought in by the continuous tubing tool and lowered to the predetermined position (generally, it is opened or closed step by step from the deepest level to the upper level step by step). Closed), the switch sleeve 30 tool can be repeatedly sealed and the inner sleeve 2 is integrated, driving the inner sleeve 2 to slide along the outer tube 1. After it is lowered to the predetermined position, the tool string is slowly lifted and lowered. The inner diameter of the normal casing is the same and consistent. There is no tonnage load change display when the switch sleeve 30 tool is lowered. In this technical solution, a convex ring part 7 is provided in the middle of the positioner 6. By setting the position of the convex ring part 7, the outer diameter of the convex ring part 7 is larger than the inner diameter of the inner sleeve 2 in the natural state. When the tool string is lowered, the convex ring part 7 slides to the initial position of the limit ring 5 and the inner sleeve 2. When the tool string is in place, the convex ring part 7 will pop outwards. By sensing the pop-up and the lifting and lowering forces, it can be judged whether the positioning unit is in place. By lifting and lowering with a certain amount of hanging force, the tonnage load change caused by the hanging can be judged that the convex ring part 7 has been stuck in the set position. After it is judged to be in place, the tool string is lifted up a certain distance by operating the continuous tubing, and then lowered to complete the track reversal through friction, and the tool string is continuously lowered to complete the sealing. At the same time, the rubber cylinder unit can be radially expanded to achieve the annular space sealing between it and the inner sliding sleeve 2, that is ... The barrel unit is compressed and expanded under the pressure of the weight load of the pipe column, and high-pressure fluid is pumped in from the annulus in a large displacement. Under the impetus of high-pressure circulation, a huge thrust is generated, forcing the switch sleeve 30 tool engaged in the inner sleeve 2 to slide downward together with the inner sleeve 2 of the sleeve part, completing the opening work of the sleeve part. After the sandblasting hole 3 is opened, the liquid and proppant are pumped into the formation from the annulus through the sandblasting hole 3 in a large displacement on the ground to complete the fracturing. When the sleeve part is opened to complete the fracturing of this section, the tool string is lifted, the seat seal is released, and the rubber barrel unit is released from the expansion state.

[0035] The rubber cylinder unit includes a rubber cylinder 9, which can radially expand to seal the annulus when the switch sleeve 30 tool seat is sealed, and an upper pressure cap 10 and a lower pressure cap 11 are arranged on both sides of the rubber cylinder 9, the lower pressure cap 11 is close to the slip 14 part, and an upper cone 12 is sleeved on the outer side of the lower pressure cap 11, and support protection rings 33 are arranged at both ends of the rubber cylinder 9; the slip 14 part includes a slip seat 13 and a plurality of slips 14 and springs 15 circumferentially arranged on the slip seat 13, the slip 14 is embedded in the slip seat 13, and both ends of the slip 14 are cones with a certain angle The two ends of the spring 15 are respectively against the middle of the slip 14 and the slip seat 13, and also include a lower cone 16 located inside the positioning sleeve and slidingly sleeved on the central tube 4. When the slip 14 is against the lower cone 16, the slip 14 can expand radially in the slip seat 13; the expansion of the slip 14 provides support for the compression of the rubber cylinder 9. The design of the slip 14 allows the slip 14 to expand radially after contacting the lower cone 16, providing a strong support force, ensuring that the rubber cylinder unit can expand smoothly and complete the annular seal with the inner sliding sleeve 2. Since the design of the slip 14 can withstand the high-pressure fluid and mechanical stress of multiple fracturing operations, the tool has a long service life, can adapt to multiple fracturing operations, and reduces the cost of frequent tool replacement. The precise matching of the spring 15, the conical surface, and the lower cone 16 of the slip 14 ensures the stability of the tool during the operation and reduces possible failures or errors in operation.

[0036] like Figure 4 As shown, the outer surface of the lower section of the central tube 4 is provided with a reversing track, and the end of the positioner 6 is provided with a rotation track as shown in FIG. Figure 5The rotating ring 17 shown has a track pin 18 fixed on it, and the end of the track pin 18 is inserted into the reversing track and slidably cooperates with the reversing track; the reversing track includes a plurality of long track grooves 19 and short track grooves 20 extending circumferentially along the center tube 4, and a reversing groove 21 connecting the tail ends of the long track grooves 19 and the tail ends of the short track grooves 20, the length of the long track grooves 19 is greater than the short track grooves 20, and the long track grooves 19 and the short track grooves 20 are arranged at intervals along the circumference of the center tube 4. The end points of the long track groove 19 and the short track groove 20 away from the reversing groove 21 are dead points, and the end points of the reversing track grooves are the track-changing dead points. When going down the well, the track pin 18 is at the dead point position on the short track, and there is a friction force between the limiter and the sleeve part. The lower cone 16 does not contact the slip 14 part, and the rubber cylinder unit is in a non-pressurized state, ensuring that the pipe string can be smoothly lowered into the well; when the convex ring part 7 reaches the predetermined position (between the gap between the inner sleeve 2 and the limit ring 5), the pipe string is lifted up and lowered, and the slip 14 and the friction block assembly enter the upper dead point of the long track from the short track, and the pipe string is lifted up and lowered, and the upper cone 12 pushes the slip 14 to open, so that it bites on the inner wall of the casing to form Support, continue to lower, the rubber cylinder 9 is compressed, the diameter becomes larger, thereby isolating the annular space of the oil casing, realizing the effect of the packer, and the high-pressure fluid is pumped into the annulus with a large displacement, and a huge thrust is generated under the impetus of the high-pressure circulation, forcing the continuous oil pipe + switch sleeve 30 tool engaged in the inner sleeve 2 and the inner sleeve 2 of the switch sleeve 30 to move downward. When the downward thrust reaches the shear force of the fixing pin of the inner sleeve 2 of the switch sleeve 30, the fixing pin is cut off, and the inner sleeve 2 is pushed to continue to move downward, completely exposing the sandblasting hole 3 of the switch sleeve 30, completing the opening work of the switch sleeve 30, and at this time, the sleeve 30 is connected with the formation, completing the circulation of the liquid in the casing and the formation. The above arrangement enables the operator to precisely control the opening and closing of the sleeve 30, especially in multi-stage fracturing operations, by opening or closing the sleeve part step by step and in sequence, ensuring that the operation at each stage can proceed smoothly, and realizing positioning and isolation operations through lifting and lowering control, saving time and manpower, and reducing the complexity of the operation. After the inner sleeve 2 is moved downward by high thrust, the fixing pin shears and pushes the inner sleeve 2 to open completely, and after the sandblasting hole 3 is exposed, the high-pressure fluid can smoothly enter the formation, effectively improving the fracturing effect of shale gas, low-permeability oil and gas layers, etc., promoting the flow of oil and gas, and increasing production.

[0037] It also includes a straightening portion, which includes an upper straightening portion and a lower straightening portion. The upper straightening portion is located on the side of the rubber cartridge unit away from the positioner 6, and the upper straightening portion includes a straightening tube 22 and a straightening body 23 circumferentially arranged on the straightening tube 22; the lower straightening portion includes a tail pipe 24 fixedly arranged on the end side of the positioner 6, the tail pipe 24 has a through hole circumferentially, a guide cone 25 is fixed to the end of the tail pipe 24, and the guide cone 25 is also circumferentially spaced with straightening bodies 23. Between the casing couplings, the tool string may get stuck due to being not centered or due to poor guidance, causing interruption of the operation. By providing a straightening portion, through the cooperation of the upper straightening portion and the lower straightening portion, the switch sleeve 30 tool can be kept centered in the casing, and the tool string can be prevented from deviating from the center of the casing during the lowering process. A straightening body 23 is provided on the guide cone at the end of the tail pipe 24. On the one hand, it can keep the tool string, especially the positioning unit, centered, and reduce the jamming caused by friction or asymmetric force; on the other hand, it is convenient for the tool string to be lowered smoothly and prevent it from getting stuck between the casing couplings; through the cooperation of the tail pipe 24 of the lower straightening portion and the guide cone 25, the tool string can remain stable during the lowering process and smoothly reach the predetermined position. A balancing valve 26 is fixedly connected to the other side of the upper pressure cap 10. The balancing valve 26 has sealing material, and the balancing valve 26 is sealed with the center pipe 4. During the lowering of the tool string of the switch sleeve 30, the balancing valve 26 is set to prevent the pressure difference between the upper and lower parts of the pipe string, so as to avoid the premature sealing of the packer rubber cylinder 9 due to the liquid pressure. The operator can ensure that the tool string can be sealed at an appropriate time when it is lowered to the predetermined position, so as to avoid repeated work due to premature sealing at an inappropriate time.

[0038] There is also a device between the upper straightening part and the rubber cylinder unit. Figure 3The release joint shown in the figure includes an upper joint 27, a lower joint 28, an elastic claw 29, a sliding sleeve 30 and a plurality of shear nails 31. The elastic claw 29 is sleeved on the sliding sleeve 30, and the upper end of the elastic claw 29 is clamped with the upper joint 27 through the circumferentially arranged shear nails 31, and the lower end of the elastic claw 29 is circumferentially sleeved on the sliding sleeve 30 and is tightened and clamped with the inner wall of the lower joint 28. Through the above arrangement, if a special situation occurs and the pipe string is stuck, since the tensile load of the coiled tubing is not very high, it cannot be pulled out within the safe load range, and the only option is to forcibly pull it off and release it (the set value is much smaller than the tensile strength of the coiled tubing), that is, use a large pulling force to pull the upper straightening part to break the shear nail 31 by pulling, so that the upper joint 27 and the lower joint 28 are separated, and then the tool is lowered for salvage or drilling and grinding. During the operation of the coiled tubing, the jamming of the tool string may cause the entire operation to be suspended, affecting the operation efficiency. Through the design of the release joint, when jamming occurs, the shear nail 31 can be broken by pulling, and the upper joint 27 and the lower joint 28 can be quickly separated to release the jammed tool string, which can ensure the smooth recovery of the tool string and reduce the downtime when it is jammed. It also includes a sandblaster 32 arranged between the balance valve 26 and the release joint. The sandblaster 32 has multiple openings circumferentially. The sandblaster 32 is used to provide liquid and proppant during the fracturing process. The sandblaster 32 has multiple openings circumferentially so that the liquid and proppant flow out of the sliding sleeve during the fracturing process and enter the formation channel. The expansion of the rubber cylinder 9 is mainly driven by pressure, so that the fracturing fluid and proppant (solids such as fracturing sand) flow out of the annulus into the formation.

[0039] The above is only an embodiment of the present invention, and the common knowledge such as the known specific technical solutions and / or characteristics in the solution is not described in detail here. It should be pointed out that for those skilled in the art, without departing from the technical solution of the present invention, several modifications and improvements can be made, which should also be regarded as the protection scope of the present invention, and these will not affect the effect of the implementation of the present invention and the practicality of the patent. The scope of protection required by this application shall be based on the content of its claims, and the specific implementation methods and other records in the specification can be used to interpret the content of the claims.

Claims

1. A switch cementing fracturing sleeve, characterized in that: The invention comprises a sleeve part and a switch sleeve tool. The sleeve part comprises an outer cylinder and an inner sleeve arranged in the outer cylinder. The outer cylinder is provided with a plurality of sandblasting holes in the circumference. The sandblasting holes can flow after the inner sleeve slides. The switch sleeve tool comprises a center tube, a rubber cylinder unit sleeved on the center tube, a slip part and a positioning unit. After the seat is sealed, the rubber cylinder unit can be radially expanded to realize the annular space sealing between the inner sleeve and the inner sleeve. A limiting ring is provided on the inner wall of the outer cylinder along the sliding direction of the inner sleeve. There is a gap between the limiting ring and the initial position of the inner sleeve. The positioning unit comprises a positioner. A convex ring part with circumferential elasticity is provided in the middle of the positioner. The outer diameter of the convex ring part is larger than the inner diameter of the inner sleeve in the natural state.

2. A switch cementing fracturing sleeve according to claim 1, characterized in that: The rubber cylinder unit comprises a rubber cylinder, and an upper pressure cap and a lower pressure cap arranged on both sides of the rubber cylinder. The lower pressure cap is close to the slip portion, an upper cone is sleeved on the outer side of the lower pressure cap, and support protection rings are arranged at both ends of the rubber cylinder.

3. A switch cementing fracturing sleeve according to claim 2, characterized in that: The slip part includes a slip seat and multiple slips and springs circumferentially arranged on the slip seat. The slip is embedded in the slip seat. Both ends of the slip are conical surfaces with a certain angle. Both ends of the spring are respectively against the middle part of the slip and the slip seat. It also includes a lower cone located inside the positioning sleeve and slidingly sleeved on the center tube. When the slip is against the lower cone, the slip can expand radially in the slip seat.

4. A switch cementing fracturing sleeve according to claim 3, characterized in that: A reversing track is arranged on the outer surface of the lower section of the central tube, a rotating ring is rotatably arranged at the end of the positioner, a track pin is fixed on the rotating ring, and the end of the track pin is inserted into the reversing track and slidably matched with the reversing track.

5. A switch cementing fracturing sleeve according to claim 4, characterized in that: The reversing track includes a plurality of long track grooves and short track grooves extending along the circumference of the central tube, and a reversing groove connecting the tail ends of the long track grooves and the tail ends of the short track grooves. The length of the long track grooves is greater than that of the short track grooves, and the long track grooves and the short track grooves are arranged at intervals along the circumference of the central tube. It also includes fixing pins, and the outer tube and the inner tube are circumferentially provided with a plurality of fixing pins for connection.

6. A switch cementing fracturing sleeve according to claim 5, characterized in that: It also includes a righting part, which includes an upper righting part and a lower righting part. The upper righting part is located on the side of the rubber cartridge unit away from the positioner, and includes a righting tube and a righting body circumferentially arranged on the righting tube; the lower righting part includes a tail pipe fixedly arranged on the end side of the positioner, the tail pipe is provided with a through hole circumferentially, a guide cone is fixed at the end of the tail pipe, and the guide cone is also provided with righting bodies at intervals circumferentially.

7. A switch cementing fracturing sleeve according to claim 6, characterized in that: A balancing valve is fixedly connected to the other side of the upper pressure cap. The balancing valve is provided with sealing material, and the balancing valve is sealed with the center pipe.

8. The switch cementing fracturing sleeve according to claim 7, characterized in that: A release joint is also provided between the upper straightening part and the rubber cylinder unit. The release joint includes an upper joint, a lower joint, an elastic claw, a sliding sleeve and multiple shear nails. The elastic claw is provided on the sliding sleeve, and the upper end of the elastic claw is clamped with the upper joint through the circumferentially arranged shear nails, and the lower end of the elastic claw is circumferentially sleeved on the sliding sleeve and is expanded and clamped with the inner wall of the lower joint.

9. A switch cementing fracturing sleeve according to claim 8, characterized in that: The utility model also comprises a sandblaster, which is provided with a plurality of openings in the circumference of the sandblaster and is arranged between the balance valve and the release joint.

10. A switch cementing fracturing sleeve according to claim 9, characterized in that: The positioner is provided with a plurality of transverse openings in the circumferential direction.

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