Fracturing string capable of detecting upper part and controlling lower part and fracturing method thereof

Abstract

The invention relates to the field of intelligent sliding sleeves, in particular to a fracturing pipe column capable of detecting the upper portion and controlling the lower portion and a fracturing method thereof, and aims to solve the technical problem that an existing intelligent sliding sleeve is unstable in performance after being standby for a long time. According to the fracturing string capable of detecting the upper part and controlling the lower part, enough distance and time are reserved for a sliding sleeve opening tool to execute a setting action in a manner of detecting the upper-stage identification short section and opening the lower-stage fracturing sliding sleeve, so that the reliability is higher; compared with the prior art, a motor and a power supply system do not need to be arranged in the fracturing sliding sleeve, after the sliding sleeve opening tool is started, setting is completed through well pressure power, meanwhile, the inner sleeve is moved away from the plugging position through well pressure, the fracturing hole channel is opened through well pressure and liquid, the design power is sufficient, and the opening success rate is high. In addition, due to the fact that the control module adopts an induction counting mode, disordered tripping-in and infinite fracturing of the fracturing sliding sleeve can be achieved.

Description

Technical Field

[0001] The invention relates to the field of intelligent sliding sleeves, and in particular to an upper inspection and lower control fracturing pipe string and a fracturing method thereof. Background Art

[0002] At present, the opening methods of conventional casing fracturing sleeves mainly include the opening method of the continuous tubing bottom belt service tool and the opening method of the input opening tool. Through actual application, it is found that the former has problems such as high construction cost, low construction efficiency, high construction risk, and low opening success rate, and its promotion is poor. The latter has the advantages of continuous pumping, unlimited stages, no cable intervention, no continuous tubing intervention, multi-cluster fracturing, good casing integrity, etc., with continuous construction, high operating efficiency and obvious technical advantages.

[0003] Conventional casing fracturing sleeves are divided into two structures: with and without differential structures. Among them, the fracturing sleeve with differential structure is mainly opened by throwing balls or darts, but the number of transformed layers is limited and it is not conducive to subsequent measures. The fracturing sleeve without differential structure is mechanically identified with the sleeve body by inserting a mechanical key. In this regard, field tests have been carried out in some wells in China, but the tests have shown that this method has problems such as inaccurate positioning, low identification success rate, and low sleeve opening success rate, which results in the loss of fracturing transformation layers.

[0004] In order to change the above situation, a smart sleeve has been proposed at home and abroad, and research has been carried out on electromagnetic wave signal transmission, pressure wave signal transmission, wireless radio frequency identification, etc. This solution mainly sends signals through the wellhead or the tool, and the downhole smart sleeve will perform the opening action after receiving the signal. It should be pointed out that this solution requires a built-in motor and power supply system in the smart sleeve, and the smart sleeve needs to standby for a long time in the high temperature and high pressure environment in the well after it is lowered into the well with the casing. In this way, the reliability of the built-in motor and power supply system will become lower and lower, which will seriously affect the success rate of opening the smart sleeve. Summary of the invention

[0005] The object of the present invention is to provide an upper inspection and lower control fracturing string and a fracturing method thereof, so as to solve the technical problem that the performance of the existing intelligent sliding sleeve is unstable after being on standby for a long time.

[0006] In order to solve the above technical problems, the technical solution provided by the present invention is:

[0007] In a first aspect, the present invention provides an inspection and control fracturing string, comprising: a top marking nipple, a fracturing sleeve, and a sleeve opening tool;

[0008] The top identification nipple is in communication with the fracturing sleeve and is also in communication with the sleeve opening tool, so that the count of the sleeve opening tool increases by 1;

[0009] The fracturing sleeve comprises an outer sleeve, a pressure cap, an inner sleeve and a sleeve identification nipple;

[0010] The outer cylinder is connected between the sleeve marking short section and the top marking short section, and along the circumference of the outer cylinder, the outer cylinder is provided with a plurality of fracturing channels penetrating through its side wall and distributed at intervals;

[0011] The pressure caps correspond to the fracturing channels one by one and are fixedly connected to the outer cylinder to block the fracturing channels;

[0012] The inner sleeve is arranged in the outer sleeve in a posture of blocking the fracturing channel, and is fixedly connected to the outer sleeve by a pin;

[0013] The inner wall of the inner sleeve is protruded to form a protrusion, and the protrusion is located between the fracturing channel and the sleeve identification nipple, and is used to abut against the sleeve opening tool that has completed the sealing;

[0014] The sleeve identification short section is spaced apart from the inner sleeve and is also in communication connection with the sleeve opening tool so that the sleeve opening tool count increases by 1;

[0015] The sliding sleeve opening tool comprises a sealing mechanism and a control mechanism, wherein the sealing mechanism comprises a pressing sleeve and a cone seat, and the control mechanism comprises an actuator and a control module;

[0016] The pressing sleeve is sleeved on the conical seat and connected to the conical seat via a tooth buckle;

[0017] The outer fixed sleeve of the cone seat is provided with a sealing ring, which contacts the end surface of the pressing sleeve and is located on the movable path of the pressing sleeve;

[0018] In the axial direction of the conical seat, the support rod of the actuator is connected between the conical seat and the pressing sleeve;

[0019] The control module is in communication with the actuator and is configured to drive the actuator to retract the support rod after the count reaches a preset value.

[0020] Furthermore, an anti-retraction locking ring is embedded in the inner wall of the pressing sleeve;

[0021] The cone seat comprises a small diameter section and a large diameter section, wherein the small diameter section is passed through the anti-retraction lock ring and connected to the anti-retraction lock ring through a horse tooth buckle, the large diameter section is integrally formed with the small diameter section, and the outer diameter of the large diameter section gradually increases from the small diameter section to a direction away from the small diameter section;

[0022] The sealing mechanism further comprises a support ring, which is sleeved on the large diameter section and contacts with an end of the sealing ring away from the pressing sleeve.

[0023] Furthermore, the pressing sleeve has a first end and a second end facing each other, wherein the inner hole of the first end is a tapered hole, and the small end of the tapered hole is directly opposite to the small diameter section, and the second end is sleeved on the large diameter section;

[0024] Along the axial direction of the cone seat, the cone seat is provided with a flow passage penetrating the cone seat, and the flow passage is communicated with the pressing sleeve;

[0025] The setting mechanism also includes a retaining ring and a soluble ball;

[0026] The retaining ring is located at the large end of the tapered hole and is fixedly connected to the pressing sleeve, and the retaining ring is provided with a return hole connected to the tapered hole;

[0027] The soluble ball is movably arranged in the tapered hole, and its diameter is larger than the diameter of the return hole and the diameter of the small end of the tapered hole.

[0028] Furthermore, the small diameter section is a stepped shaft, and the outer diameters of the stepped shaft sections decrease in sequence from the large diameter section to a direction away from the large diameter section;

[0029] The press sleeve has a stepped hole adapted to the small diameter section. In the axial direction of the press sleeve, the inner wall of the press sleeve is spaced apart from the stepped surface of the small diameter section. In the radial direction of the press sleeve, the inner wall of the press sleeve is sealed to the outer side surface of the small diameter section.

[0030] Furthermore, the setting mechanism also includes a back cap and an inner sealing tube;

[0031] The back cap is fixedly connected to the end of the large diameter section away from the small diameter section and is provided with a flow hole penetrating through it;

[0032] The inner sealing tube is located in the flow passage, and both ends of the inner sealing tube are respectively fixedly connected to the back cap and the large diameter section, and are also respectively connected to the back cap and the large diameter section;

[0033] The inner sealing tube, the back cap and the inner wall of the large diameter section together form an installation cavity, and the control module is arranged in the installation cavity.

[0034] Furthermore, the setting mechanism is made of soluble metal.

[0035] Furthermore, the sleeve identification nipple comprises a first inner protective ring, which is fixedly connected to the outer tube and has a boss at one end thereof facing the inner sleeve;

[0036] The inner walls of the inner sleeve and the first inner protective ring at opposite ends are recessed to form a groove, and the groove is adapted to the boss;

[0037] and / or, along the circumference of the outer tube, the inner wall of the outer tube is recessed to form a locking groove;

[0038] An open locking ring is embedded outside the inner sleeve, and the open locking ring is located between the locking groove and the fracturing channel.

[0039] Furthermore, the sleeve identification short section also includes a first outer protection ring, a first identification ring and a first joint;

[0040] The first outer protective ring is sleeved on the first inner protective ring and encloses the first inner protective ring to form a closed first accommodating cavity;

[0041] The first identification ring is located in the first accommodating cavity;

[0042] The first joint is fixedly connected to the first inner protective ring and the outer cylinder respectively, and the three are enclosed to form a first limiting space for limiting the movement of the first outer protective ring;

[0043] The top identification short section includes a second outer protection ring, a second identification ring, a second inner protection ring, an upper joint and a lower joint;

[0044] The second outer protective ring is sleeved on the second inner protective ring and encloses the second inner protective ring to form a closed second accommodating cavity;

[0045] The second identification ring is located in the second accommodating cavity;

[0046] The second inner protective ring is fixedly connected to the upper joint and the lower joint respectively, and the three are enclosed to form a second limiting space for limiting the movement of the second outer protective ring.

[0047] Furthermore, the inspection and control fracturing string further includes a floating collar and a floating shoe;

[0048] There are multiple fracturing sleeves, which are distributed in a straight line and fixedly connected between the floating collar and the top marking short section, and adjacent fracturing sleeves are fixedly connected.

[0049] In summary of the above technical solutions, the technical effects that can be achieved by the inspection-up and control-down fracturing string provided by the present invention are:

[0050] In the inspection and control of the fracturing string provided by the present invention, when the sleeve opening tool passes through the top identification short section, the control module count increases by 1. Each time it passes through a fracturing sleeve, that is, it passes through a corresponding sleeve identification short section, the control module count also increases by 1. After the control module count reaches the preset value, it sends a command to the actuator, and the support rod of the actuator retracts. At this time, under the action of the well pressure, the compression sleeve slides relative to the cone seat, squeezing the sealing ring, and the sealing ring is compressed and expands and seals. In this way, the sleeve opening tool completes the sealing action. Here, since the compression sleeve and the cone seat are connected by a horse tooth buckle, the compression sleeve cannot be retracted after sliding, and the sleeve opening tool will continue to maintain the sealing state.

[0051] When the sleeve opening tool that has completed the sealing continues to move to the next-level fracturing sleeve along with the pumped liquid, the protrusion of the inner sleeve of the fracturing sleeve will abut against the sleeve opening tool to prevent the sleeve opening tool from continuing to move, and the sealing ring will contact the inner wall of the inner sleeve to form a seal; continue to pump liquid, that is, to achieve pressure build-up in the pipe, and rely on the well pressure to generate thrust. When the thrust reaches a certain value, the pin is sheared off, and then the inner sleeve will slide along with the sleeve opening tool as a whole toward the sleeve identification short section of the fracturing sleeve until it abuts against the sleeve identification short section; after the inner sleeve is removed, under the combined action of the pressure and liquid in the barrel, the pressure cap is crushed, the fracturing channel is opened, and the fracturing construction is completed.

[0052] From the above, it can be seen that the inspection and control of the fracturing string reserves enough distance and time for the sleeve opening tool to perform the sealing action by detecting the upper level identification short section and opening the next level fracturing sleeve, which is more reliable. Compared with the existing technology, the fracturing sleeve does not need a built-in motor and power supply system. After the sleeve opening tool is started, the sealing is completed by the well pressure power. At the same time, the inner sleeve also moves the sealing position by the well pressure, and the fracturing channel is opened by the well pressure and liquid. The design has sufficient power and a high opening success rate. In addition, since the control module adopts the induction counting mode, the fracturing sleeve can achieve disordered lowering and unlimited fracturing.

[0053] In a second aspect, the present invention also provides a fracturing method for an upper inspection and lower control fracturing pipe string, comprising the following steps:

[0054] Lowering into the well: lower the floating collar, floating shoe, multiple fracturing sleeves, and top marking short section into the well in sequence and complete the fixing operation;

[0055] Fracturing: Set the control parameters of the control module on the ground, and then put the sleeve opening tool into the composed upper control and lower control fracturing string;

[0056] Re-fracturing: After completing a fracturing operation, the fracturing steps are repeated in sequence and the control parameters are set step by step. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] 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.

[0058] Figure 1 A schematic diagram of an application of an upper inspection and lower control fracturing string provided by an embodiment of the present invention;

[0059] Figure 2 A cross-sectional view of a fracturing sleeve provided in an embodiment of the present invention;

[0060] Figure 3 A cross-sectional view of a sleeve opening tool provided in an embodiment of the present invention before being set;

[0061] Figure 4 A cross-sectional view of a sleeve opening tool provided in an embodiment of the present invention after being set;

[0062] Figure 5 A cross-sectional view of a top marking short section provided by an embodiment of the present invention;

[0063] Figure 6 A cross-sectional view of a fracturing sleeve before opening provided by an embodiment of the present invention;

[0064] Figure 7 A cross-sectional view of an opened fracturing sleeve provided in an embodiment of the present invention.

[0065] Icon: 100-top identification short section; 110-second outer protection ring; 120-second identification ring; 130-second inner protection ring; 140-upper joint; 150-lower joint;

[0066] 200-fracturing sleeve; 210-outer cylinder; 220-pressure cap; 230-inner sleeve; 240-sleeve identification short section; 250-pin; 260-open locking ring; 270-filler; 211-fracturing channel; 212-locking groove; 231-protrusion; 232-groove; 241-first inner protective ring; 242-first outer protective ring; 243-first identification ring; 244-first joint; 2411-boss;

[0067] 300-sleeve opening tool; 310-sealing mechanism; 320-control mechanism; 311-pressing sleeve; 312-cone seat; 313-sealing ring; 314-anti-retraction locking ring; 315-support ring; 316-blocking ring; 317-soluble ball; 318-back cap; 319-inner sealing tube; 321-actuator; 322-control module; 3121-flow channel; 3161-return hole; 3181-flow hole;

[0068] 400-floating hoop and floating shoe; 500-toe end sliding sleeve. DETAILED DESCRIPTION

[0069] 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.

[0070] 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.

[0071] 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.

[0072] A smart sleeve has been proposed at home and abroad, and research has been carried out on electromagnetic wave signal transmission, pressure wave signal transmission, and wireless radio frequency identification. This solution mainly sends signals through the wellhead or the tool, and the downhole smart sleeve performs the opening action after receiving the signal. It should be pointed out that this solution requires a built-in motor and power supply system in the smart sleeve, and the smart sleeve needs to standby for a long time in the high temperature and high pressure environment in the well after it is lowered into the well with the casing. In this way, the reliability of the built-in motor and power supply system will become lower and lower, which will seriously affect the success rate of opening the smart sleeve.

[0073] In view of this, the present invention provides a fracturing string for checking and controlling the upper and lower parts, including a top identification short section 100, a fracturing sleeve 200, and a sleeve opening tool 300; the top identification short section 100 is connected to the fracturing sleeve 200, and is also connected to the sleeve opening tool 300 for communication, so that the count of the sleeve opening tool 300 is increased by 1; the fracturing sleeve 200 includes an outer cylinder 210, a pressure cap 220, an inner sleeve 230, and a sleeve identification short section 240; the outer cylinder 210 is connected to the sleeve identification short section 240 and the top identification short section 10 ... The outer cylinder 210 is provided with a plurality of fracturing channels 211 penetrating the side wall thereof and spaced apart along the circumference of the outer cylinder 210; the pressure cap 220 corresponds to the fracturing channels 211 one by one and is fixedly connected to the outer cylinder 210 to block the fracturing channels 211; the inner sleeve 230 is arranged in the outer cylinder 210 in a posture of blocking the fracturing channels 211 and is fixedly connected to the outer cylinder 210 by a pin 250; the inner wall of the inner sleeve 230 is protruded to form a protrusion 231, and the protrusion 231 is located in the fracturing channel The guide 211 and the sleeve identification short section 240 are used to abut against the sleeve opening tool 300 that has completed the setting; the sleeve identification short section 240 is spaced apart from the inner sleeve 230 and is also connected to the sleeve opening tool 300 for communication, so that the count of the sleeve opening tool 300 increases by 1; the sleeve opening tool 300 includes a setting mechanism 310 and a control mechanism 320, wherein the setting mechanism 310 includes a pressing sleeve 311 and a cone seat 312, and the control mechanism 320 includes an actuator 321 and a control module 322; The pressing sleeve 311 is sleeved on the conical seat 312 and connected to the conical seat 312 by a buckle; a sealing ring 313 is provided on the outer fixed sleeve of the conical seat 312, and the sealing ring 313 contacts the end face of the pressing sleeve 311 and is on the movable path of the pressing sleeve 311; in the axial direction of the conical seat 312, the support rod of the actuator 321 is connected between the conical seat 312 and the pressing sleeve 311; the control module 322 is communicatively connected to the actuator 321, and is configured to drive the actuator 321 to retract the support rod after the count reaches a preset value.

[0074] In the inspection and control of the fracturing string provided by the present invention, when the sleeve opening tool 300 passes through the top identification short section 100, the control module 322 count increases by 1, and each time it passes through a fracturing sleeve 200, that is, corresponding to passing through a sleeve identification short section 240, the control module 322 count also increases by 1; after the control module 322 count reaches the preset value, it sends a command to the actuator 321, and the support rod of the actuator 321 retracts. At this time, under the action of the well pressure, the press sleeve 311 slides relative to the cone seat 312, squeezes the sealing ring 313, and the sealing ring 313 is compressed and expands and seals, so that the sleeve opening tool 300 completes the sealing action. Here, since the press sleeve 311 is connected to the cone seat 312 by a horse tooth buckle, the press sleeve 311 cannot be retracted after sliding, and the sleeve opening tool 300 will continue to maintain the sealing state.

[0075] When the sleeve opening tool 300 that has completed the sealing continues to move to the next-level fracturing sleeve 200 with the pumped liquid, the protrusion 231 of the inner sleeve 230 of the fracturing sleeve 200 will abut against the sleeve opening tool 300 to prevent the sleeve opening tool 300 from continuing to move, and the sealing ring 313 will contact the inner wall of the inner sleeve 230 to form a seal; continue to pump liquid, that is, to achieve pressure build-up in the pipe, rely on the well pressure to generate thrust, and when the thrust reaches a certain value, the pin 250 is sheared off, and then the inner sleeve 230 will slide along with the sleeve opening tool 300 as a whole toward the sleeve identification short section 240 of the fracturing sleeve 200 until it abuts against the sleeve identification short section 240; after the inner sleeve 230 is removed, under the combined action of the pressure in the barrel and the liquid, the pressure cap 220 is crushed, the fracturing channel 211 is opened, and the fracturing construction is completed.

[0076] From the above, it can be seen that the inspection and control of the fracturing string reserves enough distance and time for the sleeve opening tool 300 to perform the sealing action by detecting the upper level identification short section and opening the next level fracturing sleeve 200, which is more reliable; compared with the prior art, the fracturing sleeve 200 does not need a built-in motor and power supply system. After the sleeve opening tool 300 is started, the sealing is completed by the well pressure power. At the same time, the inner sleeve 230 also moves the sealing position by the well pressure, and the fracturing channel 211 is opened by the well pressure and liquid. The design has sufficient power and a high opening success rate. In addition, since the control module 322 adopts the induction counting mode, the fracturing sleeve 200 can achieve disordered entry and unlimited fracturing.

[0077] The following combination Figures 1 to 7 The structure and shape of the upper detection and lower control fracturing string provided in this embodiment are described in detail:

[0078] Regarding the fracturing sleeve 200, specifically:

[0079] refer to Figure 2 The inner surface of the inner sleeve 230 is designed as a variable diameter structure, and the inner diameter of the upper part is larger than the inner diameter of the lower part. A ball seat, i.e., a protrusion 231, is formed at the connection between the two. The inner wall of the bottom of the inner sleeve 230 is recessed to form a group of symmetrically distributed grooves 232; a group of symmetrically distributed bosses 2411 are provided at the upper end of the first inner protective ring 241, and the bosses 2411 are adapted to the grooves 232; the pressure cap 220 is threadedly connected to the outer cylinder 210, and a high-temperature resistant filler 270 is provided in the space enclosed by the pressure cap 220, the outer cylinder 210 and the inner sleeve 230; along the circumference of the outer cylinder 210, the inner wall of the outer cylinder 210 is recessed to form a locking groove 212, and an open locking ring 260 is embedded on the outside of the inner sleeve 230, and the open locking ring 260 is located between the locking groove 212 and the fracturing channel 211.

[0080] When applying, refer to Figure 6The sleeve opening tool 300 that has completed the sealing continues to move downward with the pumped liquid to the next-stage fracturing sleeve 200 and falls on the ball seat position. The sealing ring 313 forms a seal with the inner surface of the inner sleeve 230 to achieve pressure holding in the casing; Figure 7 , relying on the thrust generated by the well pressure, the pin 250 is sheared off, the inner sleeve 230 and the sliding sleeve opening tool 300 move downward as a whole, and at the same time, the open locking ring 260 moves downward with the inner sleeve 230 to the locking groove 212 position, and the open locking ring 260 returns to its initial state, completing the locking of the inner sleeve 230 to prevent the inner sleeve 230 from retreating. At this time, the groove 232 and the boss 2411 complete the wedging action to prevent the inner sleeve 230 from rotating, thereby ensuring the fracturing effect; after the inner sleeve 230 moves downward, the pressure and liquid in the barrel flush the filler 270 and crush the pressure cap 220, thereby opening the fracturing channel 211 and completing the fracturing construction.

[0081] It should be added here that the filler 270 fills the fracturing channel 211 area, and the pressure cap 220 is made of non-metallic brittle material, which can not only transmit the internal and external pressure of the pressure cap 220 to maintain pressure balance, but also restrain the filler 270 from flowing out, avoid external cement from entering, and prevent cement from solidifying in the fracturing channel 211, thereby improving the opening success rate of the fracturing sleeve 200.

[0082] refer to Figure 2 The sleeve identification short section 240 also includes a first outer protective ring 242, a first identification ring 243 and a first joint 244; the first outer protective ring 242 is sleeved on the first inner protective ring 241, and is enclosed with the first inner protective ring 241 to form a closed first accommodating cavity; the first identification ring 243 is in the first accommodating cavity; the first joint 244 is fixedly connected to the first inner protective ring 241 and the outer cylinder 210 respectively, and the three are enclosed to form a first limiting space to limit the movement of the first outer protective ring 242;

[0083] refer to Figure 5 The top identification short section 100 includes a second outer protective ring 110, a second identification ring 120, a second inner protective ring 130, an upper joint 140 and a lower joint 150; the second outer protective ring 110 is sleeved on the second inner protective ring 130, and is enclosed with the second inner protective ring 130 to form a closed second accommodating cavity; the second identification ring 120 is in the second accommodating cavity; the second inner protective ring 130 is fixedly connected to the upper joint 140 and the lower joint 150 respectively, and the three are enclosed to form a second limiting space to limit the movement of the second outer protective ring 110.

[0084] In the sleeve identification pup joint 240 and the top identification pup joint 100, the identification ring is made of high-temperature resistant alloy permanent magnet material, and its Curie temperature is much higher than the construction well temperature, thus ensuring the long-term effectiveness and high-temperature resistance of the identification ring's magnetic field; the inner and outer protective rings are both made of non-magnetic metal materials to cover the identification ring, thus preventing the parts in contact with the identification ring from being magnetized, eliminating the phenomenon of inaccurate identification due to magnetic field disorder, and thus improving the success rate of accurate identification.

[0085] Regarding the sliding sleeve opening tool 300, specifically:

[0086] refer to Figure 3 and Figure 4 An anti-retraction locking ring 314 is embedded in the inner wall of the pressing sleeve 311; the conical seat 312 includes a small diameter section and a large diameter section, wherein the small diameter section is passed through the anti-retraction locking ring 314 and is connected to the anti-retraction locking ring 314 through a tooth buckle, the large diameter section and the small diameter section are integrally formed, and the outer diameter of the large diameter section gradually increases from the small diameter section to the direction away from the small diameter section; the sealing mechanism 310 also includes a support ring 315, which is sleeved on the large diameter section and contacts with the end of the sealing ring 313 away from the pressing sleeve 311.

[0087] Continue to refer Figure 3 and Figure 4 When the count reaches the control parameter set before entering the well, the control module 322 sends a command to the actuator 321 through the drive circuit, the locking block of the actuator 321 retracts, and the support rod loses support; under the pressure in the well, the pressure sleeve 311 slides to the right, driving the support rod to return to the cavity of the actuator 321, and at the same time, the pressure sleeve 311 squeezes the sealing ring 313 and the support ring 315, and the sealing ring 313 and the support ring 315 move along the inclined surface of the large diameter section, and expansion occurs, so that the sliding sleeve opening tool 300 completes the setting action. During the setting process, the anti-retraction lock ring 314 moves downward with the pressure sleeve 311, and is locked with the small diameter section through the horse tooth buckle, so that the sliding sleeve opening tool 300 continues to maintain the setting state.

[0088] refer to Figure 3 The pressing sleeve 311 has a first end and a second end facing each other, wherein the inner hole of the first end is a tapered hole, and the small end of the tapered hole is opposite to the small diameter section, and the second end is sleeved on the large diameter section; along the axial direction of the cone seat 312, the cone seat 312 is provided with a flow passage 3121 that runs through itself, and the flow passage 3121 is connected with the pressing sleeve 311; the sealing mechanism 310 also includes a retaining ring 316 and a soluble ball 317; the retaining ring 316 is located at the large end of the tapered hole and is fixedly connected to the pressing sleeve 311, and the retaining ring 316 is provided with a return hole 3161 connected with the tapered hole; the soluble ball 317 is movably arranged in the tapered hole, and its diameter is larger than the diameter of the return hole 3161 and the diameter of the small end of the tapered hole.

[0089] The small diameter section is a stepped shaft, and the outer diameters of each section of the stepped shaft decrease successively from the large diameter section to the direction away from the large diameter section; the pressing sleeve 311 has a stepped hole adapted to the small diameter section, and in the axial direction of the pressing sleeve 311, the inner wall of the pressing sleeve 311 is spaced apart from the stepped surface of the small diameter section, and in the radial direction of the pressing sleeve 311, the inner wall of the pressing sleeve 311 is sealed against the outer side surface of the small diameter section.

[0090] The sealing mechanism 310 also includes a back cap 318 and an inner sealing tube 319; the back cap 318 is fixedly connected to the end of the large diameter section away from the small diameter section, and is provided with a flow hole 3181 running through it; the inner sealing tube 319 is located in the flow channel 3121, and its two ends are respectively fixedly connected to the back cap 318 and the large diameter section, and are also respectively connected to the back cap 318 and the large diameter section; the inner sealing tube 319, the back cap 318 and the inner wall of the large diameter section together form an installation cavity, and the control module 322 is arranged in the installation cavity.

[0091] When applying it in specific Figure 4 As shown, the press sleeve 311 slides to the right, and in the axial direction of the press sleeve 311, the distance between the inner wall of the press sleeve 311 and the stepped surface of the small diameter section gradually decreases. When the two collide, the press sleeve 311 slides into place, and the sealing ring 313 and the support ring 315 complete the expansion and sealing. After the fracturing construction is completed, the initial blowback fluid enters the cone seat 312 from the flow hole 3181, passes through the inner sealing tube 319, flows out from the flow channel 3121 and enters the press sleeve 311, and the blowback fluid pushes the soluble ball 317, enters the cone hole, and then returns to the ground from the blowback hole 3161.

[0092] In the above design, the soluble ball 317 cooperates with the compression sleeve 311 to form a one-way valve, thereby preventing the return fluid from falling back. In addition, the sealing cooperation between the sealing ring 313 and the inner sleeve 230 and the sealing cooperation between the compression sleeve 311 and the cone seat 312 also prevents the return fluid from falling back. It should also be noted here that the sealing mechanism 310 is made of soluble metal. In the later stage of the blowout, the sealing mechanism 310 is completely dissolved, and the control module 322, the actuator 321 and other small non-soluble components will be discharged to the ground with the return fluid, thereby ensuring that there is no residue in the wellbore.

[0093] The working process of the inspection and control of the fracturing string provided in this embodiment is as follows:

[0094] Downhole: lower the floating collar and floating shoe 400, the toe sleeve 500, multiple fracturing sleeves 200, and the top identification short section 100 into the well in sequence, and complete the fixing operation; Fracturing: set the control parameters of the control module 322 on the ground, and then put the sleeve opening tool 300 into the composed fracturing string; Re-fracturing: after completing one fracturing, repeat the fracturing steps in sequence, and set the control parameters step by step.

[0095] Specifically, there is no order requirement when multiple fracturing sleeves 200 are lowered. During fracturing construction, the toe sleeve 500 is first opened by holding the casing pressure to complete the first-level fracturing construction. When the N-th level fracturing sleeve 200 needs to be opened, the control module 322 of the sleeve opening tool 300 is set on the ground with a control parameter of N, and then the set sleeve opening tool 300 is put into and pumped. When the sleeve opening tool 300 passes through the top identification short section 100, the count is 1. Each subsequent fracturing sleeve 200 passed, the count increases by 1. When the count reaches N, the sleeve opening tool 300 starts to execute the action. Here, by detecting the upper-level identification ring and making full use of the distance and pumping time between the two fracturing sleeves 200, it is ensured that the sleeve opening tool 300 has sufficient distance and time to complete the sealing action. When the sleeve opening tool 300 descends to the N-th level fracturing sleeve 200, the pressure is held to open the N-th level fracturing sleeve 200 to complete the N-th level fracturing construction.

[0096] After the Nth stage of fracturing construction is completed, it is more preferred to subsequently set control parameters step by step to open the fracturing sleeve 200 of each layer section step by step to complete the fracturing construction of each layer section.

[0097] 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 with 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 fracturing string for inspection and control, characterized in that: include: A top marking nipple (100), a fracturing sleeve (200), and a sleeve opening tool (300); The top identification nipple (100) is in communication with the fracturing sleeve (200) and is also in communication connection with the sleeve opening tool (300) so that the count of the sleeve opening tool (300) increases by 1; The fracturing sleeve (200) comprises an outer sleeve (210), a pressure cap (220), an inner sleeve (230) and a sleeve identification nipple (240); The outer cylinder (210) is connected between the sliding sleeve identification short section (240) and the top identification short section (100), and along the circumference of the outer cylinder (210), the outer cylinder (210) is provided with a plurality of fracturing channels (211) penetrating through the side wall thereof and distributed at intervals; The pressure cap (220) corresponds to the fracturing channel (211) one by one, and is fixedly connected to the outer cylinder (210) to block the fracturing channel (211); The inner sleeve (230) is disposed in the outer sleeve (210) in a posture of blocking the fracturing channel (211), and is fixedly connected to the outer sleeve (210) via a pin (250); The inner wall of the inner sleeve (230) is protruded to form a protrusion (231), and the protrusion (231) is located between the fracturing channel (211) and the sliding sleeve identification nipple (240), and is used to abut against the sliding sleeve opening tool (300) that has completed the sealing; The sleeve identification short section (240) is spaced apart from the inner sleeve (230) and is also connected to the sleeve opening tool (300) for communication, so that the count of the sleeve opening tool (300) is increased by 1; The sliding sleeve opening tool (300) comprises a setting mechanism (310) and a control mechanism (320), wherein the setting mechanism (310) comprises a pressing sleeve (311) and a cone seat (312), and the control mechanism (320) comprises an actuator (321) and a control module (322); The pressing sleeve (311) is sleeved on the conical seat (312) and connected to the conical seat (312) via a tooth buckle; The outer fixed sleeve of the cone seat (312) is provided with a sealing ring (313), the sealing ring (313) is in contact with the end surface of the pressing sleeve (311) and is located on the movable path of the pressing sleeve (311); In the axial direction of the conical seat (312), the support rod of the actuator (321) is connected between the conical seat (312) and the pressing sleeve (311); The control module (322) is communicatively connected to the actuator (321), and is configured to drive the actuator (321) to retract the support rod after the count reaches a preset value.

2. The inspection and control fracturing string according to claim 1, characterized in that: An anti-retraction locking ring (314) is embedded in the inner wall of the pressing sleeve (311); The cone seat (312) comprises a small diameter section and a large diameter section, wherein the small diameter section is inserted into the anti-retraction lock ring (314) and connected to the anti-retraction lock ring (314) via a tooth buckle, the large diameter section is integrally formed with the small diameter section, and the outer diameter of the large diameter section gradually increases from the small diameter section to a direction away from the small diameter section; The sealing mechanism (310) further comprises a support ring (315), wherein the support ring (315) is sleeved on the large diameter section and is in contact with an end of the sealing ring (313) facing away from the pressing sleeve (311).

3. The inspection and control fracturing string according to claim 2, characterized in that: The pressing sleeve (311) has a first end and a second end facing each other, wherein the inner hole of the first end is a tapered hole, and the small end of the tapered hole is directly opposite to the small diameter section, and the second end is sleeved on the large diameter section; Along the axial direction of the conical seat (312), the conical seat (312) is provided with a flow passage (3121) penetrating the conical seat (312), and the flow passage (3121) is communicated with the pressing sleeve (311); The setting mechanism (310) further comprises a retaining ring (316) and a soluble ball (317); The retaining ring (316) is located at the large end of the tapered hole and is fixedly connected to the pressing sleeve (311), and the retaining ring (316) is provided with a return hole (3161) connected to the tapered hole; The soluble ball (317) is movably disposed in the conical hole, and its diameter is larger than the diameter of the return hole (3161) and the diameter of the small end of the conical hole.

4. The inspection and control fracturing string according to claim 3, characterized in that: The small diameter section is a stepped shaft, and the outer diameters of the sections of the stepped shaft decrease in sequence from the large diameter section to a direction away from the large diameter section; The pressing sleeve (311) has a stepped hole adapted to the small-diameter section. In the axial direction of the pressing sleeve (311), the inner wall of the pressing sleeve (311) is spaced apart from the stepped surface of the small-diameter section. In the radial direction of the pressing sleeve (311), the inner wall of the pressing sleeve (311) is sealed against the outer side surface of the small-diameter section.

5. The inspection and control fracturing string according to claim 3, characterized in that: The setting mechanism (310) further comprises a back cap (318) and an inner sealing tube (319); The back cap (318) is fixedly connected to the end of the large diameter section away from the small diameter section, and is provided with a flow hole (3181) penetrating the back cap; The inner sealing tube (319) is located in the flow passage (3121), and its two ends are respectively fixedly connected to the back cap (318) and the large diameter section, and are also respectively connected to the back cap (318) and the large diameter section; The inner sealing tube (319), the back cap (318) and the inner wall of the large diameter section together form an installation cavity, and the control module (322) is arranged in the installation cavity.

6. The inspection-up and control-down fracturing string according to any one of claims 1 to 5, characterized in that: The setting mechanism (310) is made of soluble metal.

7. The inspection and control fracturing string according to claim 1, characterized in that: The sliding sleeve identification short section (240) comprises a first inner protection ring (241), the first inner protection ring (241) is fixedly connected to the outer cylinder (210), and a boss (2411) is provided at one end thereof facing the inner sleeve (230); The inner walls of the ends of the inner sleeve (230) and the first inner protective ring (241) opposite to each other are recessed to form a groove (232), and the groove (232) is adapted to fit the boss (2411); and / or, along the circumference of the outer cylinder (210), the inner wall of the outer cylinder (210) is recessed to form a locking groove (212); An open locking ring (260) is embedded outside the inner sleeve (230), and the open locking ring (260) is located between the locking groove (212) and the fracturing channel (211).

8. The inspection and control fracturing string according to claim 7, characterized in that: The sliding sleeve identification short section (240) further comprises a first outer protection ring (242), a first identification ring (243) and a first joint (244); The first outer protective ring (242) is sleeved on the first inner protective ring (241), and is enclosed with the first inner protective ring (241) to form a closed first accommodating cavity; The first identification ring (243) is located in the first accommodating cavity; The first joint (244) is fixedly connected to the first inner protective ring (241) and the outer cylinder (210) respectively, and the three are enclosed to form a first limiting space for limiting the movement of the first outer protective ring (242); The top identification short section (100) comprises a second outer protection ring (110), a second identification ring (120), a second inner protection ring (130), an upper joint (140) and a lower joint (150); The second outer protective ring (110) is sleeved on the second inner protective ring (130), and is enclosed with the second inner protective ring (130) to form a closed second accommodating cavity; The second identification ring (120) is located in the second accommodating cavity; The second inner protective ring (130) is fixedly connected to the upper joint (140) and the lower joint (150) respectively, and the three are enclosed to form a second limiting space for limiting the movement of the second outer protective ring (110).

9. The inspection and control fracturing string according to claim 1, characterized in that: The inspection and control fracturing string further comprises a floating collar and a floating shoe (400); The fracturing sleeves (200) are provided in plurality, and the plurality of fracturing sleeves (200) are distributed in a straight line and are fixedly connected between the floating collar and the floating shoe (400) and the top marking short section (100), and adjacent fracturing sleeves (200) are fixedly connected.

10. A fracturing method for an upper inspection and lower control fracturing pipe string, characterized in that: Based on the inspection and control of the fracturing string according to any one of claims 1 to 9, the method comprises the following steps: Lowering into the well: lowering the floating collar and floating shoe (400), a plurality of fracturing sleeves (200), and the top marking short section (100) into the well in sequence, and completing the fixing operation; Fracturing: setting the control parameters of the control module (322) on the ground, and then inserting the sleeve opening tool (300) into the formed upper-control-lower fracturing string; Re-fracturing: After completing a fracturing operation, the fracturing steps are repeated in sequence and the control parameters are set step by step.

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