A remote controlled expandable packer and method of using the same

Abstract

The present invention relates to a remote-controlled expandable packer and a method of using the same, and belongs to the field of downhole equipment for oil production, and specifically to a remote-controlled expandable packer for fracturing and a method of using the same, and comprises an upper joint and a lower joint, wherein the upper joint and the lower joint are connected via a packer body, a first liquid inlet hole is arranged on the rotating sleeve, and a second liquid inlet hole is arranged on the center pipe, and the central axes of the first liquid inlet hole and the second liquid inlet hole are located in the plane where the same cross section of the rotating sleeve is located; the present invention utilizes a remote control device to realize the control of a driving device, and transmits the power of the driving device to the rotating sleeve via a power transmission device to realize the rotation of the rotating sleeve, thereby realizing the conduction or blocking of the first liquid inlet hole and the second liquid inlet hole, and realizing remote control of whether the first liquid inlet hole and the second liquid inlet hole are conducted, thereby effectively avoiding the phenomenon of midway sealing during the process of going down to the well, and affecting the sealing rate and use effect of the oil field packer.

Description

Technical Field

[0001] The invention belongs to the field of downhole equipment for petroleum production, and in particular relates to a remote-controlled expansion packer for fracturing and a use method thereof. Background Art

[0002] A packer is a flexible sealing element used to seal the annular space between the tubing and the wellbore and between tubings, and to isolate the production layer in order to control the production (injection) of fluid and protect the casing as a downhole tool. It is an important tool for oil and gas field exploitation, and can provide effective mechanical means for the normal production of oil and gas wells and the smooth implementation of various downhole process measures. It occupies a very important position in the exploration and development of oil and gas fields.

[0003] The commonly used K344 steel skeleton packer is a hydraulic expansion packer, which is suspended and fixed, hydraulically set and hydraulically unsealed. The rubber tube expands outward to seal the annular space of the oil and casing. When the tool is lowered to the predetermined position, hydraulic pressure is added from the oil pipe. When the internal and external pressure difference reaches 0.5-0.7Mpa, the liquid pressure is transmitted to the rubber tube through the liquid inlet hole on the center tube, so that the rubber tube expands, seals the annular space of the oil casing, releases the pressure in the oil pipe, and the rubber tube is retracted and unsealed.

[0004] The existing expandable packers for oil fields are prone to being set during the process of being lowered into the well, which affects the setting rate and use effect of the expandable packers for oil fields. In addition, the existing expandable packers for oil fields can only be set and unsealed by hydraulic pressure. During the construction of horizontal well sliding sleeve staged fracturing, the packers cannot be selectively set and unsealed. Generally, multiple expandable packers are put into the well, and all of them are set or unsealed at one time through pressure. Multiple setting or unsealing causes the service life of the packer rubber cylinder to decrease. At the same time, using multiple packers together will generate a large setting force or unsealing force, which may easily lead to the packer being unable to be completely set or unsealed, and it is also easy to cause problems such as drill sticking, which poses a great risk. Summary of the invention

[0005] In order to solve the above problems, the present invention provides a remote-controlled expandable packer and a method for using the same which effectively solve the problems of premature setting of the packer when lowered, expansion of the rubber tube when pulled out, and inability to verify the seal during construction that occur in conventional expandable packers during construction.

[0006] The present invention discloses a remote-controlled expandable packer, comprising an upper joint and a lower joint, wherein the upper joint and the lower joint are connected through a packer body, wherein the packer body comprises a central tube and a rotating sleeve rotatably arranged in the central tube, wherein the central axis of the rotating sleeve and the central axis of the central tube are located on the same straight line, wherein a first liquid inlet hole is arranged on the rotating sleeve, and a second liquid inlet hole is arranged on the central tube, wherein the central axes of the first liquid inlet hole and the second liquid inlet hole are located in the plane where the same cross section of the rotating sleeve is located;

[0007] A rotating device is provided outside the central tube for driving the rotating sleeve to rotate and connect the first liquid inlet hole and the second liquid inlet hole. The rotating device includes a connected driving device and a power transmission device. The power transmission device passes through the central tube and is connected to the rotating sleeve.

[0008] The driving device is connected with a remote control device.

[0009] Preferably, the remote control device includes a microprocessor that receives a digital electrical signal and identifies, judges, processes the digital electrical signal and generates a corresponding control signal; the microprocessor is electrically connected to an A / D converter that converts an analog electrical signal into a digital signal;

[0010] The A / D converter is electrically connected to an acoustic-electric converter for receiving a signal and converting the signal into an analog electrical signal. The acoustic-electric converter is electrically connected to a ground control system for sending a signal to the acoustic-electric converter. The ground control system is used to emit a vibration sound wave signal.

[0011] The driving device is used to receive a control signal sent by the microprocessor and is electrically connected to the microprocessor;

[0012] The microprocessor is connected to a power supply.

[0013] Preferably, the power supply is a lithium battery.

[0014] Preferably, a charging port is provided on the lithium battery, and the charging port extends out of the packer body.

[0015] Preferably, a accommodating chamber is fixedly arranged on the circumferential surface of the central tube, and the remote control devices are all fixedly arranged in the accommodating chamber.

[0016] Preferably, there are four accommodating chambers, namely a communication chamber, a control chamber, a transmission chamber and an execution chamber. The communication chamber, the control chamber, the transmission chamber and the execution chamber are interconnected, the acoustic-electric converter and the A / D converter are fixedly arranged in the communication chamber, the microprocessor and the power supply are fixedly arranged in the control chamber, the driving device is fixedly arranged in the transmission chamber, and the power transmission device is fixedly arranged in the execution chamber.

[0017] Or preferably, the driving device is a micro reduction motor, an output shaft is rotatably provided on the micro reduction motor, an automatic switch for controlling the start and stop of the micro reduction motor is provided on the micro reduction motor, and the automatic switch is electrically connected to the microprocessor.

[0018] Preferably, the power transmission device comprises a transmission gear, the transmission gear is sleeved on the output shaft of the micro reduction motor and fixedly connected to the output shaft of the micro reduction motor, and the rotation axis of the transmission gear is parallel to the central axis of the central tube;

[0019] The rotating sleeve is provided with a rack, which is fixedly arranged on the outer circumferential surface of the rotating sleeve and laid along the circumference of the rotating sleeve. The central tube is provided with a through hole at a position corresponding to the rack, and the gear is meshed with the rack after extending through the hole.

[0020] A method for using a remote-controlled expandable packer is provided. The remote-controlled expandable packer is assembled with a sleeve and a pipe string on the ground. Specifically, a primary packer is connected with a primary sleeve, and the primary packer is located on the upper part of the primary sleeve; a secondary sleeve is connected with the primary packer and the secondary packer; the secondary sleeve is located on the upper part of the primary packer, and the secondary packer is located on the upper part of the secondary sleeve... and so on, to complete the connection of the entire fracturing pipe string;

[0021] At this time, the first liquid inlet hole and the second liquid inlet hole of the packer are misaligned, that is, the first liquid inlet hole and the second liquid inlet hole are in a closed state. The ground pipe string is lowered into the wellbore according to the construction requirements to carry out the first stage of fracturing. First, the primary packer is opened. The specific operation is: a vibration sound wave signal is sent through the ground control system. After the acoustic-to-electric converter receives the vibration sound wave signal, it converts the vibration sound wave signal into an analog electrical signal. The analog electrical signal is converted into a digital signal through an A / D converter and transmitted to a microprocessor through the A / D converter. The microprocessor identifies, judges, processes the digital electrical signal and generates a corresponding control signal;

[0022] After receiving the control signal, the automatic switch controls the micro-reduction motor to turn on, and the micro-reduction motor drives the transmission gear to rotate, and the transmission gear meshes with the rack on the rotating sleeve, so that the first liquid inlet hole and the second liquid inlet hole overlap, thereby realizing the opening of the first liquid inlet hole and the second liquid inlet hole on the first-stage packer, and then the ground pressure is applied to realize the setting of the first-stage packer. At this time, only the first-stage packer is in the setting state, and the other multi-stage packers on the upper part are in the unsetting state. Therefore, the top of the first-stage packer is connected to the wellhead. Continuing to pressurize can verify the setting effect of the first-stage packer. If the setting is good, continue to pressurize to open the first-stage constant pressure sliding sleeve and perform the first stage fracturing;

[0023] After the first stage of fracturing is completed, a vibration signal is sent through the ground control system to open the secondary packer, complete the setting of the secondary packer, and drop a ball to open the secondary sliding sleeve. At the same time, the setting effect of the secondary packer is verified. If the setting is good, the second stage of fracturing is carried out... and so on, to complete the fracturing construction of the third, fourth, and even all sections of the horizontal well. After the construction is completed, the oil pipe is depressurized to complete the unsealing of the packer, and a vibration signal is sent through the ground control system to close the first and second liquid inlet holes of all the packers. After the blowout, the construction string is removed, and the entire fracturing construction is completed.

[0024] The present invention has a simple structure and is easy to use. A remote control device is used to control the driving device, and the power of the driving device is transmitted to the rotating sleeve through a power transmission device to realize the rotation of the rotating sleeve, thereby realizing the connection or blocking of the first liquid inlet hole and the second liquid inlet hole. Remote control of whether the first liquid inlet hole and the second liquid inlet hole are connected is realized, which effectively avoids the phenomenon of mid-way sealing during the process of going down to the well, affecting the sealing rate and use effect of the oil field sealer.

[0025] The present invention discloses a remote-controlled expandable packer. A first liquid inlet hole is designed on a rotating sleeve, and a second liquid inlet hole is arranged on a central tube. The opening and closing of the liquid inlet hole of the packer is controlled by rotating the rotating sleeve, that is, the connection and blocking of the first liquid inlet hole and the second liquid inlet hole. When the packer is lowered, the liquid inlet hole of the packer is in a closed state, which can effectively solve the problem of the packer being sealed midway during the process of being lowered into the well. During construction, the opening of the liquid inlet hole of the packer is controlled by a signal, and the upper part of the packer is connected with the wellhead through the casing. The sealing condition of the packer can be verified by the casing pressure, which solves the problem that the packer cannot be verified during the staged fracturing of the horizontal well. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a schematic diagram of the structure of the present invention.

[0027] Figure 2 for Figure 1 A magnified view of the remote control device.

[0028] Figure 3 Schematic diagram of the rotating sleeve.

[0029] Figure 4 for Figure 1 A is an enlarged view of the middle image.

[0030] Figure 5 This is a schematic diagram of the assembly of the packer, sleeve and pipe string.

[0031] Figure markings: 1-upper joint, 2-packer body, 3-lower joint, 4-remote control device, 5-center tube, 6-rotating sleeve, 7-execution chamber, 8-transmission chamber, 9-control chamber, 10-communication chamber, 11-acoustic-electric converter, 12-A / D converter, 13-microprocessor, 14-micro reduction motor, 15-transmission gear, 16-power supply, 17-rack, 18-first liquid inlet, 19-second liquid inlet. DETAILED DESCRIPTION

[0032] The present invention discloses a remote-controlled expandable packer, comprising an upper joint 1 and a lower joint 3, wherein the upper joint 1 and the lower joint 3 are connected via a packer body 2, wherein the packer body 2 comprises a central tube 5 and a rotating sleeve 6 rotatably disposed in the central tube 5, wherein the central axis of the rotating sleeve 6 is located on the same straight line as the central axis of the central tube 5, wherein the rotating sleeve 6 is provided with a first liquid inlet hole 18, and the central tube 5 is provided with a second liquid inlet hole 19, wherein the central axes of the first liquid inlet hole 18 and the second liquid inlet hole 19 are located in the plane where the same cross section of the rotating sleeve 6 is located;

[0033] The central tube 5 is provided with a rotating device for driving the rotating sleeve 6 to rotate and connect the first liquid inlet hole 18 and the second liquid inlet hole 19. The rotating device includes a connected driving device and a power transmission device. The power transmission device passes through the central tube 5 and is connected to the rotating sleeve 6.

[0034] The driving device is connected to a remote control device 4 .

[0035] In one embodiment, the remote control device 4 includes a microprocessor 13 that receives a digital electrical signal and identifies, determines, processes, and generates a corresponding control signal. The microprocessor 13 is electrically connected to an A / D converter 12 that converts an analog electrical signal into a digital signal.

[0036] The A / D converter 12 is electrically connected to an acoustic-to-electric converter 11 for receiving a signal and converting the signal into an analog electrical signal, and the acoustic-to-electric converter 11 is electrically connected to a ground control system for sending a signal to the acoustic-to-electric converter 11;

[0037] The driving device is used to receive a control signal sent by the microprocessor 13 and is electrically connected to the microprocessor 13;

[0038] The microprocessor 13 is connected to a power supply 16 .

[0039] The power supply 16 is a lithium battery.

[0040] In one embodiment, a charging port is provided on the lithium battery, and the charging port extends out of the packer body 2 .

[0041] In one embodiment, a accommodating chamber is fixedly disposed on the circumference of the central tube 5 , and the remote control devices 4 are all fixedly disposed in the accommodating chamber.

[0042] There are four accommodating chambers, namely a communication chamber 10, a control chamber 9, a transmission chamber 8 and an execution chamber 7. The communication chamber 10, the control chamber 9, the transmission chamber 8 and the execution chamber 7 are interconnected. The acoustic-to-electric converter 11 and the A / D converter 12 are fixedly arranged in the communication chamber 10, the microprocessor 13 and the power supply 16 are fixedly arranged in the control chamber 9, the driving device is fixedly arranged in the transmission chamber 8, and the power transmission device is fixedly arranged in the execution chamber 7.

[0043] In one embodiment, the driving device is a micro reduction motor 14 , the micro reduction motor 14 is rotatably provided with an output shaft, the micro reduction motor 14 is provided with an automatic switch for controlling the start and stop of the micro reduction motor 14 , and the automatic switch is electrically connected to the microprocessor 13 .

[0044] The power transmission device includes a transmission gear 15, which is sleeved on the output shaft of the micro-reduction motor 14 and fixedly connected to the output shaft of the micro-reduction motor 14, and the rotation axis of the transmission gear 15 is parallel to the central axis of the central tube 5;

[0045] The rotating sleeve 6 is provided with a rack 17, which is fixedly arranged on the outer peripheral surface of the rotating sleeve 6 and laid circumferentially along the rotating sleeve 6. The central tube 5 is provided with a through hole at a position corresponding to the rack 17, and the gear is meshed with the rack 17 after passing through the hole.

[0046] A method for using a remote-controlled expandable packer is provided. The remote-controlled expandable packer is assembled with a sleeve and a pipe string on the ground. Specifically, a primary packer is connected with a primary sleeve, and the primary packer is located on the upper part of the primary sleeve; a secondary sleeve is connected with the primary packer and the secondary packer; the secondary sleeve is located on the upper part of the primary packer, and the secondary packer is located on the upper part of the secondary sleeve... and so on, to complete the connection of the entire fracturing pipe string;

[0047] At this time, the first liquid inlet hole 18 and the second liquid inlet hole 19 of the packer are misaligned, that is, the first liquid inlet hole 18 and the second liquid inlet hole 19 are in a closed state. The ground pipe string is lowered into the wellbore according to the construction requirements to carry out the first stage of fracturing. First, the primary packer is opened. The specific operation is: a vibration sound wave signal is sent through the ground control system. After the acoustic-to-electric converter 11 receives the vibration sound wave signal, it converts the vibration sound wave signal into an analog electrical signal. The analog electrical signal is converted into a digital signal through the A / D converter 12, and is transmitted to the microprocessor 13 through the A / D converter 12. The microprocessor 13 identifies, judges, processes the digital electrical signal and generates a corresponding control signal;

[0048] After receiving the control signal, the automatic switch controls the micro-reduction motor 14 to turn on, and the micro-reduction motor 14 drives the transmission gear 15 to rotate, and the transmission gear 15 meshes with the rack 17 on the rotating sleeve 6, so that the first liquid inlet hole 18 and the second liquid inlet hole 19 overlap, thereby realizing the opening of the first liquid inlet hole 18 and the second liquid inlet hole 19 on the first-stage packer, and then the ground is pressurized to realize the setting of the first-stage packer. At this time, only the first-stage packer is in the setting state, and the other multi-stage packers on the upper part are in the unsetting state. Therefore, the top of the first-stage packer is connected to the wellhead. Continuing to pressurize can verify the setting effect of the first-stage packer. If the setting is good, continue to pressurize to open the first-stage constant pressure sliding sleeve and perform the first stage fracturing;

[0049] After the first stage of fracturing is completed, a vibration signal is sent through the ground control system to open the secondary packer, complete the sealing of the secondary packer, and drop a ball to open the secondary sleeve. At the same time, the sealing effect of the secondary packer is verified. If the sealing effect is good, the second stage of fracturing is carried out. And so on, the fracturing construction of the third section, the fourth section and even all sections of the horizontal well is completed. After the construction is completed, the oil pipe is depressurized to complete the unsealing of the packer, and the first liquid inlet hole 18 and the second liquid inlet hole 19 of all the packers are closed by sending a vibration signal through the ground control system. After the blowout, the construction pipe is removed, and the entire fracturing construction is completed.

[0050] The present invention discloses a remote-controlled expandable packer. A first liquid inlet hole 18 is designed on a rotating sleeve 6, and a second liquid inlet hole 19 is arranged on a central pipe 5. The opening and closing of the liquid inlet hole of the packer is controlled by rotating the rotating sleeve 6, that is, the connection and blocking of the first liquid inlet hole 18 and the second liquid inlet hole 19. When the packer is lowered, the liquid inlet hole of the packer is in a closed state, which can effectively solve the problem of the packer being sealed midway during the process of being lowered into the well. During construction, the opening of the liquid inlet hole of the packer is controlled by a signal, and the upper part of the packer is connected to the wellhead through the casing. The sealing condition of the packer can be verified by the casing pressure, which solves the problem that the packer cannot be verified during the staged fracturing of the horizontal well.

[0051] The devices in this solution are all prior art. For example, the acoustic-electric converter 11, the A / D converter 12 and the microprocessor 13 are all consistent with those in the patent application No. 201410121668.1, entitled "Remote Alarm System for Farmland Fire Based on Photoacoustic Effect".

Claims

1. A remote-controlled expandable packer, comprising an upper joint (1) and a lower joint (3), wherein the upper joint (1) and the lower joint (3) are connected via a packer body (2), wherein the packer body (2) comprises a central tube (5) and a rotating sleeve (6) rotatably arranged in the central tube (5), wherein the central axis of the rotating sleeve (6) is located on the same straight line as the central axis of the central tube (5), wherein the rotating sleeve (6) is provided with a first liquid inlet hole (18), and the central tube (5) is provided with a second liquid inlet hole (19), wherein: The central axes of the first liquid inlet hole (18) and the second liquid inlet hole (19) are located in the same cross-sectional plane of the rotating sleeve (6); A rotating device is provided outside the central tube (5) for driving the rotating sleeve (6) to rotate so as to connect the first liquid inlet hole (18) and the second liquid inlet hole (19); The first liquid inlet hole (18) and the second liquid inlet hole (19) overlap, the first liquid inlet hole (18) and the second liquid inlet hole (19) are opened, and then ground pressure is applied to achieve the setting of the packer; When the packer is lowered, the first liquid inlet hole (18) and the second liquid inlet hole (19) of the packer are in a closed state; The rotating device comprises a driving device and a power transmission device connected to each other, and the power transmission device passes through the central tube (5) and is connected to the rotating sleeve (6); The driving device is connected to a remote control device (4).

2. A remote controlled expandable packer as claimed in claim 1, characterized in that: The remote control device (4) comprises a microprocessor (13) for receiving a digital electrical signal and identifying, judging, processing the digital electrical signal and generating a corresponding control signal; the microprocessor (13) is electrically connected to an A / D converter (12) for converting an analog electrical signal into a digital signal; The A / D converter (12) is electrically connected to an acoustic-electric converter (11) for receiving a signal and converting the signal into an analog electrical signal, and the acoustic-electric converter (11) is electrically connected to a ground control system for sending a signal to the acoustic-electric converter (11); The driving device is used to receive a control signal sent by the microprocessor (13) and is electrically connected to the microprocessor (13); The microprocessor (13) is connected to a power supply (16).

3. A remote controlled expandable packer as claimed in claim 2, characterized in that: The power supply (16) is a lithium battery.

4. A remote controlled expandable packer as claimed in claim 3, characterized in that: The lithium battery is provided with a charging port, and the charging port extends out of the packer body (2).

5. A remote controlled expandable packer as claimed in claim 4, characterized in that: A accommodating chamber is fixedly arranged on the circumferential surface of the central tube (5), and the remote control devices (4) are all fixedly arranged in the accommodating chamber.

6. A remote controlled expandable packer as claimed in claim 5, characterized in that: The accommodating chambers are arranged in four parts, namely a communication chamber (10), a control chamber (9), a transmission chamber (8) and an execution chamber (7); the communication chamber (10), the control chamber (9), the transmission chamber (8) and the execution chamber (7) are interconnected; the acoustic-electric converter (11) and the A / D converter (12) are fixedly arranged in the communication chamber (10); the microprocessor (13) and the power supply (16) are fixedly arranged in the control chamber (9); the driving device is fixedly arranged in the transmission chamber (8); and the power transmission device is fixedly arranged in the execution chamber (7).

7. A remote controlled expandable packer according to any one of claims 2 to 6, characterized in that: The driving device is a micro reduction motor (14), an output shaft is rotatably provided on the micro reduction motor (14), an automatic switch for controlling the start and stop of the micro reduction motor (14) is provided on the micro reduction motor (14), and the automatic switch is electrically connected to the microprocessor (13).

8. A remote controlled expandable packer as claimed in claim 7, characterized in that: The power transmission device comprises a transmission gear (15), the transmission gear (15) being sleeved on an output shaft of the micro-reduction motor (14) and fixedly connected to the output shaft of the micro-reduction motor (14), and the rotation axis of the transmission gear (15) being parallel to the central axis of the central tube (5); The rotating sleeve (6) is provided with a rack (17), the rack (17) is fixedly arranged on the outer peripheral surface of the rotating sleeve (6) and laid along the circumference of the rotating sleeve (6), the central tube (5) is provided with a through hole at a position corresponding to the rack (17), and the gear is inserted into the through hole and meshes with the rack (17).

9. A method for using a remotely controlled expandable packer, characterized in that: On the ground, the remote-controlled expandable packer as claimed in claim 8 is assembled with the sliding sleeve and the pipe string, specifically: the primary packer is connected with the primary sliding sleeve, and the primary packer is located on the upper part of the primary sliding sleeve; the secondary sliding sleeve is connected with the primary packer and the secondary packer; the secondary sliding sleeve is located on the upper part of the primary packer, and the secondary packer is located on the upper part of the secondary sliding sleeve, and so on, to complete the connection of the entire fracturing pipe string; At this time, the first liquid inlet hole (18) and the second liquid inlet hole (19) of the packer are misaligned, that is, the first liquid inlet hole (18) and the second liquid inlet hole (19) are in a closed state. The ground pipe string is lowered into the wellbore according to the construction requirements to carry out the first stage of fracturing. First, the primary packer is opened. The specific operation is: a vibration sound wave signal is sent through the ground control system. After the acoustic-to-electric converter (11) receives the vibration sound wave signal, it converts the vibration sound wave signal into an analog electric signal. The analog electric signal is converted into a digital signal through the A / D converter (12), and is transmitted to the microprocessor (13) through the A / D converter (12). The microprocessor (13) identifies, judges, processes the digital electric signal and generates a corresponding control signal; After receiving the control signal, the automatic switch controls the micro reduction motor (14) to turn on, and the micro reduction motor (14) drives the transmission gear (15) to rotate, and the transmission gear (15) meshes with the rack (17) on the rotating sleeve (6), so that the first liquid inlet hole (18) and the second liquid inlet hole (19) overlap, thereby realizing the opening of the first liquid inlet hole (18) and the second liquid inlet hole (19) on the first-stage packer, and then the first-stage packer is set by ground pressure. At this time, only the first-stage packer is in a set state, and the other multi-stage packers on the upper part are in an unset state. Therefore, the top of the first-stage packer is in a connected state with the wellhead. Continuing to pressurize can verify the setting effect of the first-stage packer. If the setting is good, continue to pressurize to open the first-stage constant pressure sliding sleeve and perform the first stage fracturing; After the first stage of fracturing is completed, a vibration signal is sent through the ground control system to open the secondary packer, and the secondary packer is set. A ball is dropped to open the secondary sleeve, and the setting effect of the secondary packer is verified. If the setting is good, the second stage of fracturing is carried out. In this way, the third stage, the fourth stage, and all the stages of the horizontal well are completed. After the construction is completed, the oil pipe is depressurized, the packer is unsealed, and a vibration signal is sent through the ground control system to close the first liquid inlet hole (18) and the second liquid inlet hole (19) of all the packers. After the spraying, the construction pipe string is removed, and the entire fracturing construction is completed.

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