Hydraulic switch sliding sleeve, separate-layer fracturing pipe column and using method

Abstract

The invention relates to the technical field of oil and gas field development, in particular to a hydraulic switch sliding sleeve, a separate layer fracturing pipe column and a using method, and aims to solve the problems of complex construction process, large workload, high construction cost and long construction period in the fracturing process. The hydraulic switch sliding sleeve comprises a sliding sleeve cylinder, an inner closing sliding sleeve, a pawl sliding sleeve and an opening sliding sleeve, wherein the inner closing sliding sleeve and the pawl sliding sleeve are inserted into the sliding sleeve cylinder, and the sliding sleeve cylinder is sleeved with the opening sliding sleeve. The pawl sliding sleeve is arranged below the inner closing sliding sleeve; a sand blasting opening is formed in the side wall of the sliding sleeve cylinder; in the initial state, the pawl sliding sleeve and the opening sliding sleeve block the sand blasting opening on the inner side and the outer side of the sliding sleeve cylinder correspondingly. The hydraulic opening and closing action of the sliding sleeve is achieved through ball throwing, separate layer fracturing and separate layer testing operation can be achieved through one pipe column, the operation efficiency is improved, the operation difficulty, workload and risk are reduced, the construction cost can be effectively reduced, and the construction period is shortened.

Description

Technical Field

[0001] The invention relates to the technical field of oil and gas field development, and in particular to a hydraulic switch sleeve, a layered fracturing string and a use method thereof. Background Art

[0002] At present, the "sleeve + packer" multi-stage layered fracturing technology in the casing has become an important means of reservoir transformation. However, with the continuous deepening of oil and gas resource development, water outflow from the reservoir after fracturing has become more and more common, and gas wells are seriously producing water or even stopping production during production. During the fracturing construction process, the sleeve of the conventional "sleeve + packer" layered fracturing string cannot be closed after opening, and can only be tested separately. It is impossible to achieve separate testing of each layer section, which is not conducive to the analysis and understanding of each layer section, and cannot provide an effective reference for the optimization of subsequent construction technology, construction scale, and improvement of fracturing effect. Therefore, in order to have a clearer understanding of the reservoir situation, the site usually adopts the method of single-layer fracturing, single-layer testing, and sealing to complete the fracturing and testing operations of each layer section step by step. After drilling the plug, the production string is lowered for combined production of each layer section. There are problems such as complex construction technology, many processes, and heavy workload. It is necessary to repeatedly lower the string for operation, high construction cost, and long construction period. Summary of the invention

[0003] The purpose of the present invention is to provide a hydraulic switch sleeve, a layered fracturing pipe column and a use method to solve the problems of complex construction process, large workload, high construction cost and long construction period in the fracturing process.

[0004] In order to solve the above technical problems, the technical solution provided by the present invention is:

[0005] A hydraulic switch sleeve comprises a sleeve body, an inner closing sleeve and a ratchet sleeve inserted into the sleeve body, and an opening sleeve sleeve mounted on the sleeve body; the ratchet sleeve is arranged below the inner closing sleeve; a sandblasting port is arranged on the side wall of the sleeve body; in an initial state, the ratchet sleeve and the opening sleeve respectively block the sandblasting port on the inner and outer sides of the sleeve body; after the first-stage fracturing ball is inserted, the ratchet sleeve can move downward to make the ratchet sleeve avoid the sandblasting port, and then the liquid in the sleeve body passes through the sandblasting port and pushes the opening sleeve to move downward to make the opening sleeve avoid the sandblasting port; after the second-stage fracturing ball is inserted, the inner closing sleeve moves downward to block the sandblasting port.

[0006] Furthermore, the lower end of the ratchet sleeve is a claw-shaped structure, and a ratchet limiting groove is provided on the inner wall of the sleeve body; after the first-stage fracturing ball is put in, the first-stage fracturing ball falls into the lower end of the ratchet sleeve and drives the ratchet sleeve to move downward; when the claw-shaped structure of the ratchet sleeve moves to the ratchet limiting groove, the claw-shaped structure opens and embeds into the ratchet limiting groove, and the first-stage fracturing ball can pass through the ratchet sleeve.

[0007] Furthermore, an opening step is provided on the inner wall of the opening sliding sleeve, and in an initial state, the opening step is located below the sandblasting port.

[0008] Furthermore, the area of ​​the lower end surface of the opening sliding sleeve is larger than the area of ​​the upper end surface.

[0009] Furthermore, the hydraulic switch sleeve also includes a release pin and an opening shear pin. The release pin is inserted into the ratchet sleeve and the sleeve body at the same time, and the opening shear pin is inserted into the opening sleeve and the sleeve body at the same time. After the first-stage fracturing ball is put into place, the release pin is sheared off, and the ratchet sleeve moves downward to avoid the sandblasting port. The liquid in the sleeve body pressurizes the opening step through the sandblasting port to shear off the opening shear pin.

[0010] Furthermore, the hydraulic switch sleeve also includes a closing pin and an open ring; the closing pin is inserted into the sleeve body and the inner closing sleeve at the same time; the outer wall of the inner closing sleeve is provided with a first annular groove, and the inner wall of the sleeve body is provided with a second annular groove; in an initial state, the open ring is sleeved on the inner closing sleeve and clamped in the first annular groove; after the inner closing sleeve moves downward to seal the sandblasting port, the open ring is clamped in the first annular groove and the second annular groove at the same time.

[0011] Furthermore, the hydraulic switch sleeve also includes a nozzle and a locking ring; the nozzle is inserted into the sandblasting port, and the locking ring is sleeved on the nozzle and is clamped on the nozzle and the sandblasting port at the same time.

[0012] Furthermore, the sliding sleeve body includes an upper joint, a connecting sleeve and a lower joint; the upper joint is inserted into the connecting sleeve and threadedly connected to the connecting sleeve, and the connecting sleeve is inserted into the lower joint and threadedly connected to the lower joint; the sandblasting port is opened in the connecting sleeve, and the ratchet limit groove is opened in the lower joint.

[0013] In another aspect of the present invention, a layered fracturing string is proposed, comprising at least two of the above-mentioned hydraulic switch sleeves, which are arranged as a first-stage hydraulic switch sleeve and a second-stage hydraulic switch sleeve; the second-stage hydraulic switch sleeve is arranged at one end of the first-stage hydraulic switch sleeve close to the wellhead; the first-stage fracturing ball can pass through the second-stage hydraulic switch sleeve and enter the pawl sleeve of the first-stage hydraulic switch sleeve, and the diameter of the second-stage fracturing ball is larger than that of the first-stage fracturing ball; after the second-stage fracturing ball is put into the casing, the second-stage fracturing ball drives the pawl sleeve of the second-stage hydraulic switch sleeve to move and can enter the first-stage hydraulic switch sleeve, and then drives the inner closing sleeve of the first-stage hydraulic switch sleeve to move.

[0014] In a third aspect of the present invention, a method for using a layered fracturing string is provided, using the layered fracturing string, comprising the following steps:

[0015] Interlayer isolation: The first-stage fracturing ball is put into the wellhead, and the first-stage fracturing ball falls into the ratchet sleeve of the first-stage hydraulic switch sleeve and drives the ratchet sleeve downward under the action of pressure to open the sandblasting port from the inner side of the sleeve body. As the pressure increases, all hydraulic packers on the pipe string are sealed;

[0016] First-stage fracturing: Continue to increase the pressure, the liquid passes through the sandblasting port of the first-stage hydraulic switch sleeve and pushes the opening sleeve downward to make the opening sleeve avoid the sandblasting port. At this time, the sandblasting port is fully opened, and the first-stage fracturing construction is carried out. After the fracturing construction is completed, the first layer of spraying and testing operations are carried out;

[0017] Second-stage fracturing: a second-stage fracturing ball is put into the wellhead, and the second-stage fracturing ball falls into the ratchet sleeve of the second-stage hydraulic switch sleeve and drives the ratchet sleeve downward under the action of pressure to open the sandblasting port from the inner side of the sleeve body, and then the second-stage fracturing ball falls into the inner closing sleeve of the first-stage hydraulic switch sleeve and drives the inner closing sleeve of the first-stage hydraulic switch sleeve downward to close the sandblasting port of the first-stage hydraulic switch sleeve; the pressure is increased, the liquid passes through the sandblasting port of the second-stage hydraulic switch sleeve and pushes the opening sleeve downward to make the opening sleeve avoid the sandblasting port, at which time the sandblasting port is fully opened, and the second-stage fracturing construction is carried out. After the fracturing construction is completed, the second layer of spraying and testing operations are carried out;

[0018] Multi-stage fracturing: Repeat the second-stage fracturing steps, complete the opening and closing actions of the hydraulic switch sleeve step by step, and complete the layered fracturing and layered testing operations of each layer step by step.

[0019] Based on the above technical solutions, the technical effects that can be achieved by the present invention are:

[0020] The hydraulic switch sleeve provided by the present invention comprises a sleeve body, an inner closing sleeve and a ratchet sleeve inserted into the sleeve body, and an opening sleeve sleeved into the sleeve body; the ratchet sleeve is arranged below the inner closing sleeve; a sandblasting port is arranged on the side wall of the sleeve body; in an initial state, the ratchet sleeve and the opening sleeve respectively block the sandblasting port on the inner and outer sides of the sleeve body, and after the first-stage fracturing ball is put in, the ratchet sleeve can move downward to make the ratchet sleeve avoid the sandblasting port, and then the liquid in the sleeve body passes through the sandblasting port and pushes the opening sleeve to move downward to make the opening sleeve avoid the sandblasting port; after the second-stage fracturing ball is put in, the inner closing sleeve moves downward to block the sandblasting port.

[0021] The hydraulic switch sleeve provided by the present invention has the ability to complete multi-stage layered fracturing by arranging a pawl sleeve, an opening sleeve and an inner closing sleeve, so that the hydraulic switch sleeve can realize layer-by-layer fracturing testing, each layer section can be tested separately, and the injected fracturing balls do not need to be dissolved or drilled out, which simplifies the construction steps, reduces the workload and construction costs, and shortens the construction period.

[0022] Specifically, when the hydraulic switch sleeve is used for fracturing the tubing, each hydraulic switch sleeve corresponds to a layer section, and the order from the bottom of the wellbore to the wellhead is the first-stage hydraulic switch sleeve and the second-stage hydraulic switch sleeve. After the first-stage fracturing ball is put in, the first-stage fracturing ball first drives the ratchet sleeve of the first-stage hydraulic switch sleeve to move downward, and then the first-stage fracturing ball continues to fall to the bottom of the tubing for plugging. At this time, only the ratchet sleeve moves, and the opening sleeve does not move to keep the sandblasting port of the first-stage hydraulic switch sleeve in a blocked state, so that the inside of the tubing is not connected to the wellbore annulus, and the pressure inside the tubing is not released, so that each packer can be seated to complete the separation of each layer section. As the pressure increases, the liquid in the tubing passes through the sandblasting port of the first-stage hydraulic switch sleeve and pushes the opening sleeve downward to open the sandblasting port to perform fracturing, blowout and testing of the first layer. Then the second-stage fracturing ball is put in, which first drives the ratchet sleeve of the second-stage hydraulic switch sleeve downward, and then the second-stage fracturing ball continues to fall to the inner closing sleeve of the first-stage hydraulic switch sleeve. Since the opening sleeve has not descended at this time, the sandblasting port of the second-stage hydraulic switch sleeve is still blocked, and the tubing above the second-stage fracturing ball is not connected to the wellbore annulus, so the pressure in the tubing can be maintained so that it can push the second-stage fracturing ball, and then the inner closing sleeve of the first-stage hydraulic switch sleeve is pushed downward by the second-stage fracturing ball to close the sandblasting port of the first-stage hydraulic switch sleeve. Then, the pressure can be continued to be applied to make the opening sleeve of the second-stage hydraulic switch sleeve descend to open the sandblasting port, and the second layer of fracturing, blowout and testing can be carried out. In this way, more layers of fracturing, blowout and testing can be carried out. It should be noted that the closer to the wellhead, the larger the diameter of the fracturing ball used.

[0023] In short, the cooperation of the ratchet sleeve, the opening sleeve and the inner closing sleeve ensures the setting of the packer and the opening and closing of the sandblasting ports of each layer. At the same time, only one fracturing ball is actually required for each layer, that is, one fracturing ball can complete the sealing of the sandblasting ports of the previous layer and the opening of the sandblasting ports of the current layer. There is no need to perform any processing on the fracturing ball during the working process, such as drilling out the fracturing ball or waiting for the fracturing ball to dissolve. The innovative design of the structure of the tubing and the tool itself ensures the smooth flow of the ball delivery channel, and the sleeve switch action and the tubing layered fracturing and layered testing functions can be performed at any time, which effectively reduces the difficulty of work and improves work efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0025] Figure 1 A schematic diagram of the structure of a hydraulic switch sleeve provided in an embodiment of the present invention;

[0026] Figure 2 It is a schematic diagram of the first-stage fracturing ball seat on the ratchet sliding sleeve;

[0027] Figure 3 It is a schematic diagram of the downward release of the ratchet sliding sleeve;

[0028] Figure 4 The figure is a schematic diagram of opening the sliding sleeve;

[0029] Figure 5 A schematic diagram of a second-stage fracturing ball seat closing the sliding sleeve internally;

[0030] Figure 6 The figure is a schematic diagram of closing the inner closing sleeve;

[0031] Figure 7 for Figure 1 AA section view in;

[0032] Figure 8 Schematic diagram of the structure of the layered fracturing string.

[0033] Icons: 100-sleeve body; 200-inner closing sleeve; 300-ratchet sleeve; 400-opening sleeve; 500-release pin; 600-opening shear pin; 700-closing pin; 800-opening ring; 900-nozzle; 1000-locking ring; 110-upper joint; 120-connecting sleeve; 130-lower joint; 140-setting screw; 10a-sandblasting port; 10b-ratchet limit groove; a-first-stage fracturing ball; b-second-stage fracturing ball; 10-first-stage hydraulic switch sleeve; 20-second-stage hydraulic switch sleeve; 30-seat ball seat; 40-first-stage hydraulic packer; 50-first-stage hydraulic anchor; 60-second-stage hydraulic packer; 70-second-stage hydraulic anchor; 80-safety joint. DETAILED DESCRIPTION

[0034] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0035] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0036] Some embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. In the absence of conflict, the following embodiments and features in the embodiments can be combined with each other.

[0037] In order to have a clearer understanding of the reservoir conditions, single-layer fracturing, single-layer testing and sealing methods are usually adopted to complete the fracturing and testing operations of each layer step by step. After drilling the plug, the production tubing is lowered to carry out combined production of each layer. This has the problems of complex construction technology, many steps, heavy workload, repeated operation of the tubing, high construction cost and long construction period.

[0038] In view of this, the present invention provides a hydraulic switch sleeve, comprising a sleeve body 100, an inner closing sleeve 200 and a ratchet sleeve 300 inserted in the sleeve body 100, and an opening sleeve 400 sleeved in the sleeve body 100; the ratchet sleeve 300 is arranged below the inner closing sleeve 200; a sandblasting port 10a is arranged on the side wall of the sleeve body 100; in an initial state, the ratchet sleeve 300 and the opening sleeve 400 are respectively The inner and outer sides of the cylinder 100 block the sandblasting port 10a. After the first-stage fracturing ball a is put in, the ratchet sleeve 300 can move downward to make the ratchet sleeve 300 avoid the sandblasting port 10a. Then, the liquid in the sleeve cylinder 100 passes through the sandblasting port 10a and pushes the opening sleeve 400 to move downward to make the opening sleeve 400 avoid the sandblasting port 10a. After the second-stage fracturing ball b is put in, the inner closing sleeve 200 moves downward to block the sandblasting port 10a.

[0039] The hydraulic switch sleeve provided by the present invention has the ability to complete multi-stage layered fracturing by arranging a pawl sleeve 300, an opening sleeve 400 and an inner closing sleeve 200, so that the hydraulic switch sleeve can realize layer-by-layer fracturing testing, each layer section can be tested separately, and the injected fracturing balls do not need to be dissolved or drilled out, which simplifies the construction steps, reduces the workload and construction costs, and shortens the construction period.

[0040] Specifically, when the hydraulic switch sleeve is used for fracturing the tubing, each hydraulic switch sleeve corresponds to a layer section, and the order from the bottom of the wellbore to the wellhead is the first-stage hydraulic switch sleeve 10 and the second-stage hydraulic switch sleeve 20. After the first-stage fracturing ball a is put in, the first-stage fracturing ball a first drives the ratchet sleeve 300 of the first-stage hydraulic switch sleeve 10 to move downward, and then the first-stage fracturing ball a continues to fall to the bottom of the tubing for plugging. At this time, only the ratchet sleeve 300 moves, and the opening sleeve 400 does not move to keep the sandblasting port 10a of the first-stage hydraulic switch sleeve 10 in a blocked state, so that the inside of the tubing is not connected to the wellbore annulus, and the pressure inside the tubing is not released, so that each packer can be seated to complete the separation of each layer section. As the pressure increases, the liquid in the tubing passes through the sandblasting port 10a of the first-stage hydraulic switch sleeve 10 and pushes the opening sleeve 400 downward to open the sandblasting port 10a to perform fracturing, release and testing of the first layer. Then the second-stage fracturing ball b is put in, and the second-stage fracturing ball b first drives the ratchet sleeve 300 of the second-stage hydraulic switch sleeve 20 to move downward, and then the second-stage fracturing ball b continues to fall to the inner closing sleeve 200 of the first-stage hydraulic switch sleeve 10. Since the opening sleeve 400 has not descended at this time, the sandblasting port 10a of the second-stage hydraulic switch sleeve 20 is still blocked, and the tubing above the second-stage fracturing ball b is not connected to the wellbore annulus, so the pressure in the tubing can be maintained so that it can push the second-stage fracturing ball b, and then the inner closing sleeve 200 of the first-stage hydraulic switch sleeve 10 is pushed downward by the second-stage fracturing ball b to close the sandblasting port 10a of the first-stage hydraulic switch sleeve 10. Then, the pressure can be continued to make the opening sleeve 400 of the second-stage hydraulic switch sleeve 20 descend to open the sandblasting port 10a, and the second layer of fracturing, spraying and testing can be carried out. In this way, more layers of fracturing, blowing and testing can be carried out. It should be noted that the closer to the wellhead, the larger the diameter of the fracturing ball used.

[0041] In short, the cooperation of the ratchet sleeve 300, the opening sleeve 400 and the inner closing sleeve 200 ensures the sealing of the packer and the opening and closing of the sandblasting ports 10a of each layer. At the same time, only one fracturing ball is actually required for each layer, that is, one fracturing ball can complete the sealing of the sandblasting ports 10a of the previous layer and the opening of the sandblasting ports 10a of the current layer. In addition, there is no need to perform any processing on the fracturing balls during the working process, such as drilling out the fracturing balls or waiting for the fracturing balls to dissolve. The innovative design of the structure of the tubing and the tool itself ensures the smooth flow of the ball delivery channel, and the sleeve switch action and the tubing layered fracturing and layered testing functions can be performed at any time, which effectively reduces the difficulty of work and improves work efficiency.

[0042] The following combination Figure 1-Figure 7 The structure and shape of the hydraulic switch sleeve provided in this embodiment are described in detail:

[0043] In an optional solution of this embodiment, the sliding sleeve body 100 includes an upper joint 110, a connecting sleeve 120, a lower joint 130 and a set screw 140. Figure 2 As shown. The two ends of the connecting sleeve 120 are respectively threadedly connected with the upper joint 110 and the lower joint 130. Specifically, the upper joint 110 is inserted into the connecting sleeve 120 and threadedly connected with the connecting sleeve 120, the connecting sleeve 120 is inserted into the lower joint 130 and threadedly connected with the lower joint 130, the set screw 140 is inserted into the side wall of the connecting sleeve 120 and threadedly connected with the connecting sleeve 120, and the set screw 140 abuts against the outer wall of the upper joint 110 to prevent the threaded connection between the upper joint 110 and the connecting sleeve 120 from loosening. Similarly, the set screw 140 is inserted into the side wall of the lower joint 130 and threadedly connected with the lower joint 130, and abuts against the outer wall of the connecting sleeve 120 to prevent the threaded connection between the lower joint 130 and the connecting sleeve 120 from loosening. In addition, the end of the upper joint 110 away from the connecting sleeve 120 is provided with an internal thread for connecting with a tool string, and the end of the lower joint 130 away from the connecting sleeve 120 is provided with an external thread for connecting with a tool string.

[0044] In an optional solution of this embodiment, the hydraulic switch sleeve further includes a release pin 500 and an opening shear pin 600. Figure 1 , Figure 7 As shown, the release pin 500 is inserted into the ratchet sliding sleeve 300 and the connecting sleeve 120 at the same time to achieve locking of the two, and the opening shear pin 600 is inserted into the opening sliding sleeve 400 and the connecting sleeve 120 at the same time to achieve locking of the two.

[0045] In an optional solution of this embodiment, the hydraulic switch sleeve further includes a closing pin 700 and an open ring 800. Figure 1 As shown, the closing pin 700 is inserted into the connecting sleeve 120 and the inner closing sleeve 200 at the same time to achieve locking of the two; the outer wall of the inner closing sleeve 200 is provided with a first annular groove, and the inner wall of the connecting sleeve 120 is provided with a second annular groove; in the initial state, the open ring 800 is sleeved on the inner closing sleeve 200 and clamped in the first annular groove, and after the inner closing sleeve 200 moves downward to block the sandblasting port 10a, the open ring 800 is clamped in the first annular groove and the second annular groove at the same time to lock the position of the inner closing sleeve 200. Specifically, the open ring 800 is set as a C-shaped ring.

[0046] In the optional solution of this embodiment, the hydraulic switch sleeve also includes a nozzle 900 and a locking ring 1000; the side wall of the connecting sleeve 120 is provided with a sandblasting port 10a, the nozzle 900 is inserted into the sandblasting port 10a, and the locking ring 1000 is sleeved on the nozzle 900 and is simultaneously clamped to the nozzle 900 and the sandblasting port 10a to prevent the nozzle 900 from falling off. That is, the locking ring 1000 is set as a C-shaped ring, which is equivalent to a retaining spring, and the inner wall of the sandblasting port 10a and the outer wall of the nozzle 900 are both provided with an annular groove to be clamped with the locking ring 1000, such as Figure 2 , Figure 7 Specifically, two nozzles 900 and two release pins 500 are provided, and the two nozzles 900 and the two release pins 500 are evenly distributed in a ring around the axis of the connecting sleeve 120 and are spaced apart from each other.

[0047] In this embodiment, the lower end of the ratchet sleeve 300 is an elastic claw-shaped structure, which is restricted by the connecting sleeve 120 and is initially in a compressed state; the inner wall of the lower joint 130 is provided with a ratchet limiting groove 10b, such as Figure 1 As shown. Specifically, the claw-shaped structure is to cut a groove in the lower end of the ratchet sleeve 300 along the axial direction. When the claw-shaped structure loses the restriction of the inner wall of the connecting sleeve 120, the claw-shaped structure can be opened to fit into the ratchet limiting groove 10b, so that the lower end of the ratchet sleeve 300 abuts against the ratchet limiting groove 10b and the fracturing ball can be separated from the ratchet sleeve 300. A retaining edge is provided at the lower end of the claw-shaped structure to block the fracturing ball, that is, each claw can be provided as an L-shaped plate. After the fracturing ball is put into the device, the fracturing ball falls into the lower end of the ratchet sleeve 300 and abuts against one side of the L-shaped plate to drive the ratchet sleeve 300 to move downward; when the claw-shaped structure of the ratchet sleeve 300 moves to the ratchet limiting groove 10b, the claw-shaped structure opens and fits into the ratchet limiting groove 10b, and the fracturing ball can pass through the ratchet sleeve 300.

[0048] In this embodiment, the inner wall of the opening sleeve 400 is provided with an opening step. In the initial state, the opening step is located below the sandblasting port 10a. When the liquid passes through the nozzle 900, pressure can be applied to the opening step to push the opening sleeve 400 to move downward. Furthermore, the area of ​​the lower end surface of the opening sleeve 400 is larger than the area of ​​the upper end surface to prevent the liquid pressure outside the hydraulic switch sleeve from causing the opening sleeve 400 to open prematurely during the lowering process. Due to the area difference between the upper and lower ends, the pressure of the external liquid causes the opening sleeve 400 to have a tendency to move upward. In the initial state, the pressure of the external liquid can cause the opening sleeve 400 to abut against the step of the outer wall of the connecting sleeve 120, such as Figure 1 shown.

[0049] The working process of the hydraulic switch sleeve provided in this embodiment is as follows:

[0050] After the first-stage fracturing ball a is put into the housing, the first-stage fracturing ball a falls into the ratchet sleeve 300 and abuts against the claw-shaped structure of the ratchet sleeve 300. Figure 2 As the pressure increases, the release pin 500 is sheared off, and the ratchet sleeve 300 moves downward to avoid the sandblasting port 10a. When the claw structure moves to the ratchet stop groove 10b, the claw structure opens to engage with the ratchet stop groove 10b and abuts against the ratchet stop groove 10b, thereby preventing the ratchet sleeve 300 from moving further downward. At the same time, the ratchet sleeve 300 releases the first-stage fracturing ball a. Figure 3As shown in the figure, the liquid in the sliding sleeve body 100 continues to be pressurized and reaches the opening step through the nozzle 900, thereby pushing the opening sliding sleeve 400 to shear the opening shear pin 600, and then pushing the opening sliding sleeve 400 downward to connect the sliding sleeve body 100 with the annular space of the wellbore, completing the opening of the sandblasting port 10a, as shown in the figure. Figure 4 shown.

[0051] When the sandblasting port 10a needs to be closed, the second-stage fracturing ball b is inserted, and the second-stage fracturing ball b is seated in the inner closing sleeve 200. Figure 5 As shown, the second-stage fracturing ball b then pushes the inner closing sleeve 200 under pressure, thereby shearing off the closing pin 700 and pushing the inner closing sleeve 200 downward. When the opening ring 800 is moved to align with the second annular groove, the opening ring 800 opens to simultaneously engage with the first annular groove and the second annular groove, thereby locking the position of the inner closing sleeve 200. At this time, the lower end of the inner closing sleeve 200 abuts against the upper end of the ratchet sleeve 300, as shown in FIG. Figure 6 shown.

[0052] Based on the hydraulic switch sleeve provided in this embodiment, a layered fracturing string is proposed, including at least two of the above-mentioned hydraulic switch sleeves, which are arranged as a first-stage hydraulic switch sleeve 10 and a second-stage hydraulic switch sleeve 20, such as Figure 8 As shown, the second-stage hydraulic switch sleeve 20 is arranged at one end of the first-stage hydraulic switch sleeve 10 close to the wellhead; the first-stage fracturing ball a can pass through the second-stage hydraulic switch sleeve 20 and enter the ratchet sleeve 300 of the first-stage hydraulic switch sleeve 10, and the diameter of the second-stage fracturing ball b is larger than that of the first-stage fracturing ball a, that is, the diameters of the fracturing balls corresponding to the hydraulic switch sleeves of each stage are different, and the sizes of the corresponding parts will be adjusted according to the size of the fracturing balls. After the second-stage fracturing ball b is put into operation, the second-stage fracturing ball b drives the ratchet sleeve 300 of the second-stage hydraulic switch sleeve 20 to move and enter the first-stage hydraulic switch sleeve 10, and then drives the inner closing sleeve 200 of the first-stage hydraulic switch sleeve 10 to move.

[0053] In this embodiment, the layered fracturing string further includes a sealing ball seat 30, a first-stage hydraulic packer 40, a first-stage hydraulic anchor 50, a second-stage hydraulic packer 60, a second-stage hydraulic anchor 70 and a safety joint 80. Figure 8As shown, from the bottom of the wellbore to the wellhead, there are a sealing ball seat 30, a first-level hydraulic packer 40, a first-level hydraulic anchor 50, a first-level hydraulic switch sleeve 10, a second-level hydraulic packer 60, a second-level hydraulic anchor 70, a second-level hydraulic switch sleeve 20 and a safety joint 80. Furthermore, more levels of hydraulic switch sleeves and hydraulic packers can be set to perform layer-by-layer fracturing tests in more sections. Among them, the hydraulic anchor is a conventional fracturing tool, and the casing is anchored by the anchor claw during the construction process to prevent the pipe column from creeping; the safety joint 80 is a hydraulic or mechanical hand-release tool, which can release the pipe column when the pipe column is buried in sand; the sealing ball seat 30 is a conventional ball seat pressure-holding tool, and the ball is thrown to hold the pressure to complete the sealing of the pipe column packer.

[0054] Based on the layered fracturing string provided in this embodiment, a method for using the layered fracturing string is proposed, which uses the layered fracturing string and includes the following steps:

[0055] Interlayer isolation: The layered fracturing string is lowered to the designed well depth, and the first-stage fracturing ball a is dropped into the wellhead. The first-stage fracturing ball a falls into the ratchet sleeve 300 of the first-stage hydraulic switch sleeve 10, and the pressure is held at 10MPa. Under the action of pressure, the first-stage fracturing ball a drives the ratchet sleeve 300 to cut off the release pin 500, and then drives the ratchet sleeve 300 downward and snaps into the ratchet limit groove 10b, as shown in FIG. Figure 2 As shown, at this time, the first-stage fracturing ball a can be separated from the pawl limiting groove 10b and seated on the sealing ball seat 30, and the sandblasting port 10a is opened from the inner side of the connecting sleeve 120, as shown in FIG. Figure 3 As shown. Then the pressure value is further increased to 15MPa. As the pressure increases, all the hydraulic packers on the string are set, thereby achieving interlayer isolation. It should be noted that at this time, if the opening sleeve 400 is missing or the opening sleeve 400 is started in advance, it will cause pressure relief and the pressure cannot be increased to 15MPa to ensure the hydraulic packer is set.

[0056] First stage fracturing: Continue to increase the pressure to 25MPa, the liquid passes through the sandblasting port 10a of the first stage hydraulic switch sleeve 10 and pushes the opening sleeve 400 to move downward so that the opening sleeve 400 cuts off the opening shear pin 600 and moves downward to avoid the sandblasting port 10a. At this time, the sandblasting port 10a is fully opened. Figure 4 As shown, the first stage fracturing construction can be carried out subsequently, and after the fracturing construction is completed, the first layer of blowdown and testing operations can be carried out.

[0057] Second stage fracturing: The second stage fracturing ball b is put into the wellhead, and the second stage fracturing ball b falls into the ratchet sleeve 300 of the second stage hydraulic switch sleeve 20, and the pressure is 10MPa. Figure 5As shown. Under the action of pressure, the second-stage fracturing ball b drives the ratchet sleeve 300 to cut off the release pin 500, and then drives the ratchet sleeve 300 downward and snaps into the ratchet limit groove 10b. At this time, the second-stage fracturing ball b can be separated from the ratchet limit groove 10b and seated on the opening sleeve 400 of the first-stage hydraulic switch sleeve 10. At the same time, the sandblasting port 10a of the second-stage hydraulic switch sleeve 20 is opened from the inner side of the connecting sleeve 120. Then, the second-stage fracturing ball b drives the inner closing sleeve 200 of the first-stage hydraulic switch sleeve 10 to cut off the closing pin 700 and move downward, and the open ring 800 snaps into the second annular slot, completing the closing action of the first-stage hydraulic switch sleeve 10, that is, the sandblasting hole of the first-stage hydraulic switch sleeve 10 is closed. Figure 6 Then the pressure value is further increased to 25 MPa, the liquid passes through the sandblasting port 10a of the second-stage hydraulic switch sleeve 20 and pushes the opening sleeve 400 to move downward so that the opening sleeve 400 cuts off the opening shear pin 600 and moves downward to avoid the sandblasting port 10a, at which time the sandblasting port 10a is fully opened, and then the second-stage fracturing construction is carried out, and the second layer of spraying and testing operations are carried out after the fracturing construction is completed.

[0058] It should be noted that if the opening sleeve 400 of the second-stage hydraulic switch sleeve 20 is missing or the opening sleeve 400 is opened in advance, the sandblasting port 10a will be completely opened, and the 10MPa pressure cannot be maintained, and the closing action of the first-stage hydraulic switch sleeve 10 cannot be completed. Closing the first-stage hydraulic switch sleeve 10 can ensure the stable and accurate conduct of the second-stage fracturing and testing, provide a guarantee for accurate analysis and understanding of each layer, and provide an accurate reference basis for the subsequent optimization of construction technology and construction scale and the improvement of fracturing effect.

[0059] Multi-stage fracturing: Repeat the second-stage fracturing steps, complete the opening and closing actions of the hydraulic switch sleeve step by step, and complete the layered fracturing and layered testing operations of each layer step by step.

[0060] The layered fracturing string provided in this embodiment realizes the hydraulic opening and closing action of the sliding sleeve by throwing a ball. The process is mature and reliable, and the on-site operation is simple. The layered fracturing and layered testing operations can be realized in one trip of the string, which improves the operation efficiency, reduces the operation difficulty, workload and risk, and can effectively reduce the construction cost and shorten the construction period.

[0061] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A hydraulic switch sleeve, characterized in that: It comprises a sliding sleeve body (100), an inner closing sliding sleeve (200) and a ratchet sliding sleeve (300) inserted into the sliding sleeve body (100), and an opening sliding sleeve (400) sleeved on the sliding sleeve body (100); the ratchet sliding sleeve (300) is arranged below the inner closing sliding sleeve (200); A sandblasting port (10a) is provided on the side wall of the sliding sleeve body (100); In the initial state, the ratchet sleeve (300) and the opening sleeve (400) respectively block the sandblasting port (10a) at the inner and outer sides of the sleeve body (100); after the first-stage fracturing ball (a) is put in, the ratchet sleeve (300) can move downward so that the ratchet sleeve (300) avoids the sandblasting port (10a); then, the liquid in the sleeve body (100) passes through the sandblasting port (10a) and pushes the opening sleeve (400) to move downward so that the opening sleeve (400) avoids the sandblasting port (10a); After the second-stage fracturing ball (b) is put in, the inner closing sleeve (200) moves downward to seal the sandblasting port (10a).

2. The hydraulic switch sleeve according to claim 1, characterized in that: The lower end of the ratchet sliding sleeve (300) is a claw-shaped structure, and the inner wall of the sliding sleeve body (100) is provided with a ratchet limiting groove (10b); After the first-stage fracturing ball (a) is put in, the first-stage fracturing ball (a) falls into the lower end of the ratchet sliding sleeve (300) and drives the ratchet sliding sleeve (300) to move downward; When the claw-shaped structure of the ratchet sliding sleeve (300) moves to the ratchet limiting groove (10b), the claw-shaped structure opens and embeds into the ratchet limiting groove (10b), and at this time the first-stage fracturing ball (a) can pass through the ratchet sliding sleeve (300).

3. The hydraulic switch sleeve according to claim 2, characterized in that: The inner wall of the opening sliding sleeve (400) is provided with an opening step, and in an initial state, the opening step is located below the sandblasting port (10a).

4. The hydraulic switch sleeve according to claim 3, characterized in that: The area of ​​the lower end surface of the opening sliding sleeve (400) is larger than the area of ​​the upper end surface.

5. The hydraulic switch sleeve according to claim 3, characterized in that: It also includes a release pin (500) and an opening shear pin (600), wherein the release pin (500) is inserted into the ratchet sliding sleeve (300) and the sliding sleeve body (100) at the same time, and the opening shear pin (600) is inserted into the opening sliding sleeve (400) and the sliding sleeve body (100) at the same time; After the first-stage fracturing ball (a) is put in, the release pin (500) is sheared off, and the ratchet sliding sleeve (300) moves downward to avoid the sandblasting port (10a); The liquid in the sliding sleeve body (100) passes through the sandblasting port (10a) to pressurize the opening step to shear off the opening shear pin (600).

6. The hydraulic switch sleeve according to claim 5, characterized in that: Also included is a closing pin (700) and an open ring (800); The closing pin (700) is inserted into the sliding sleeve body (100) and the inner closing sliding sleeve (200) at the same time; The outer wall of the inner closing sliding sleeve (200) is provided with a first annular groove, and the inner wall of the sliding sleeve body (100) is provided with a second annular groove; In an initial state, the open ring (800) is sleeved on the inner closing sleeve (200) and is clamped in the first annular groove; after the inner closing sleeve (200) moves downward to block the sandblasting port (10a), the open ring (800) is simultaneously clamped in the first annular groove and the second annular groove.

7. The hydraulic switch sleeve according to claim 6, characterized in that: Also includes a nozzle (900) and a locking ring (1000); The nozzle (900) is inserted into the sandblasting port (10a), and the locking ring (1000) is sleeved on the nozzle (900) and is simultaneously clamped to the nozzle (900) and the sandblasting port (10a).

8. The hydraulic switch sleeve according to claim 7, characterized in that: The sliding sleeve body (100) comprises an upper joint (110), a connecting sleeve (120) and a lower joint (130); The upper joint (110) is inserted into the connecting sleeve (120) and is threadedly connected to the connecting sleeve (120); the connecting sleeve (120) is inserted into the lower joint (130) and is threadedly connected to the lower joint (130); The sandblasting port (10a) is provided on the connecting sleeve (120), and the ratchet limiting groove (10b) is provided on the lower joint (130).

9. A layered fracturing string, characterized in that: Comprising at least two hydraulic switch sleeves according to any one of claims 1 to 8, arranged as a first-stage hydraulic switch sleeve (10) and a second-stage hydraulic switch sleeve (20); The second-stage hydraulic switch sleeve (20) is arranged at one end of the first-stage hydraulic switch sleeve (10) close to the wellhead; the first-stage fracturing ball (a) can pass through the second-stage hydraulic switch sleeve (20) and enter the ratchet sleeve (300) of the first-stage hydraulic switch sleeve (10); the diameter of the second-stage fracturing ball (b) is larger than that of the first-stage fracturing ball (a); After the second-stage fracturing ball (b) is put into operation, the second-stage fracturing ball (b) drives the ratchet sleeve (300) of the second-stage hydraulic switch sleeve (20) to move and enter the first-stage hydraulic switch sleeve (10), and then drives the inner closing sleeve (200) of the first-stage hydraulic switch sleeve (10) to move.

10. A method for using a layered fracturing string, using the layered fracturing string as claimed in claim 9, characterized in that: The steps include: Interlayer isolation: a first-stage fracturing ball (a) is dropped into the wellhead, and the first-stage fracturing ball (a) falls into the ratchet sleeve (300) of the first-stage hydraulic switch sleeve (10) and drives the ratchet sleeve (300) downward under the action of pressure so that the sandblasting port (10a) is opened from the inner side of the sleeve body (100), and as the pressure increases, all hydraulic packers on the pipe string are set; First-stage fracturing: the pressure is continuously increased, the liquid passes through the sandblasting port (10a) of the first-stage hydraulic switch sleeve (10) and pushes the opening sleeve (400) to move downward so that the opening sleeve (400) avoids the sandblasting port (10a), at which time the sandblasting port (10a) is fully opened, and the first-stage fracturing construction is carried out. After the fracturing construction is completed, the first layer of spraying and testing operations are carried out; Second-stage fracturing: a second-stage fracturing ball (b) is dropped into the wellhead, the second-stage fracturing ball (b) falls into the ratchet sleeve (300) of the second-stage hydraulic switch sleeve (20) and drives the ratchet sleeve (300) downward under the action of pressure so that the sandblasting port (10a) is opened from the inner side of the sleeve body (100), and then the second-stage fracturing ball (b) falls into the inner closing sleeve (200) of the first-stage hydraulic switch sleeve (10) and drives the first-stage hydraulic switch sleeve (10) downward. The inner closing sleeve (200) moves downward to close the sandblasting port (10a) of the first-stage hydraulic switch sleeve (10); the pressure is increased, and the liquid passes through the sandblasting port (10a) of the second-stage hydraulic switch sleeve (20) and pushes the opening sleeve (400) to move downward so that the opening sleeve (400) avoids the sandblasting port (10a). At this time, the sandblasting port (10a) is fully opened, and the second-stage fracturing construction is carried out. After the fracturing construction is completed, the second layer of spraying and testing operations are carried out; Multi-stage fracturing: Repeat the second-stage fracturing steps to complete the opening and closing actions of the hydraulic switch sleeve step by step, and at the same time complete the layered fracturing and layered testing operations of each layer step by step.

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