CN114135236A

CN114135236A - Coiled tubing conveying resistance reducing device and using method

Info

Publication number: CN114135236A
Application number: CN202111494118.0A
Authority: CN
Inventors: 章娅菲; 钞锐; 窦益华; 曹银萍
Original assignee: Xian Shiyou University
Current assignee: Xian Shiyou University
Priority date: 2021-12-08
Filing date: 2021-12-08
Publication date: 2022-03-04
Anticipated expiration: 2041-12-08
Also published as: CN114135236B

Abstract

The invention discloses a coiled tubing conveying resistance reducing device and a using method thereof, wherein the coiled tubing conveying resistance reducing device comprises a limiting mechanism, a resistance reducing mechanism, a control mechanism, a power mechanism and a shell; the coiled tubing conveying and resistance reducing device is arranged in an annular space between the coiled tubing and a casing/open hole well wall, and is arranged to be put into a well along with the coiled tubing during installation, and is anchored near the position of a self-locking point of the coiled tubing in a resistance reducing working state, wherein the position is obtained by calculation according to a well body structure and related parameters of the used coiled tubing; the invention has the characteristics of economy, practicability, simple structure and convenient operation and maintenance.

Description

Coiled tubing conveying resistance reducing device and using method

Technical Field

The invention belongs to the technical field of coiled tubing downhole tools, and particularly relates to a coiled tubing conveying resistance reducing device and a using method thereof.

Background

In recent years, during the running operation of a horizontal well, a highly deviated well, a vertical well and the like by using a coiled tubing, in the processes of drilling and running, because the coiled tubing generates and accumulates axial friction force on a well along a tubing string, and when the tubing string runs into the well, the friction force between the coiled tubing and a casing consumes part of effective load of a well mouth, the coiled tubing has buckling and self-locking phenomena, the coiled tubing still does not go deep after circulating for a plurality of times, the coiled tubing cannot reach a preset position, the site construction progress of the coiled tubing is severely restricted, the time-stopping cost of construction and the like is increased, the subsequent operation cannot be performed, and the well completion operation of the whole well is influenced.

The existing underground tractor, namely an underground crawler, also called an underground crawling mechanism, an underground tractor, an underground traction robot, an underground hydraulic pressurizer, an underground drill bit propeller and the like, is an underground tool capable of providing traction force at the well bottom, and can be divided into 3 types, namely a roller crawling type, a track crawling type (caterpillar track type) and a grasping arm telescopic sliding type (stepping type), according to the motion principle of the underground tractor. However, most of the existing domestic tractors have the defects of complex structure, poor reliability, large underground friction resistance, difficult running and taking out, difficult application of bit pressure and the like due to the design reason.

Disclosure of Invention

In order to overcome the technical problems, the invention aims to provide a coiled tubing conveying resistance reducing device and a using method thereof.

In order to achieve the purpose, the invention adopts the technical scheme that:

a coiled tubing conveying resistance reducing device comprises a limiting mechanism, a resistance reducing mechanism, a control mechanism, a power mechanism and a shell;

the coiled tubing conveying resistance reducing device is arranged in an annulus between the coiled tubing and a casing/open hole well wall, and is arranged to enter a well along with the coiled tubing, and is anchored near a self-locking point of the coiled tubing in a resistance reducing working state;

the limiting mechanism is used for locking the coiled tubing along the radial inward movement and is put in/out together with the coiled tubing;

the drag reduction mechanism is used for converting sliding friction between the coiled tubing and the casing/open hole well wall into rolling friction;

the control mechanism is used for receiving a ground signal instruction, controlling the limiting mechanism to move inwards or outwards along the radial direction, locking the coiled tubing by moving inwards, and clamping the casing/open hole well wall by moving outwards;

the power mechanism is used for providing power for the movement of the limiting mechanism;

the shell coats the limiting mechanism, the resistance reducing mechanism, the control mechanism and the power mechanism into a whole.

The limiting mechanism is arranged along the radial direction of the coiled tubing conveying drag reduction device, the movement direction of the limiting mechanism is along the radial direction to move inwards or outwards, the limiting mechanism can be locked/unlocked according to requirements after moving inwards or outwards to any position, the limiting mechanism moves along the radial direction to move outwards to clamp the casing/open hole well wall, the coiled tubing is released at the same time, and the coiled tubing conveying drag reduction device is anchored at the position of the coiled tubing which is easy to self-lock.

The inner side and the outer side of the limiting mechanism are respectively provided with a pawl, the pawl tooth shapes of the inner side and the outer side are both inclined downwards, and the lower pawl of the inner side of the limiting mechanism is helpful for locking the inner continuous oil pipe when the continuous oil pipe conveying resistance reducing device is lifted out; the lower helical teeth on the outer side of the limiting mechanism are beneficial to anchoring the peripheral casing/open hole well wall by the coiled tubing conveying resistance reducing device during auxiliary conveying, and displacement is prevented.

The drag reduction mechanism is arranged on the inner side wall surface of the continuous oil pipe conveying drag reduction device to reduce the conveying resistance of the continuous oil pipe, the drag reduction mechanism is a ball or a crawler, and when and only when the continuous oil pipe conveying drag reduction device reaches a specified working position (self-locking point), the drag reduction mechanism is in contact with the continuous oil pipe, so that the sliding friction between the continuous oil pipe and the casing pipe/open hole well wall is converted into the rolling friction between the drag reduction mechanism and the continuous oil pipe.

The shell plays a role in supporting and fixing.

The limiting mechanism comprises a claw 1-1 and a main bevel gear disc 1-2;

the resistance reducing mechanism comprises a resistance reducing lining 2-1 and resistance reducing balls 2-2;

the control mechanism comprises ground control equipment 3-1 and an underground receiving device 3-2;

the power mechanism comprises a motor 4-1 and a bevel gear 4-2;

the shell comprises an upper shell 5-1 and a lower shell 5-2;

the motor 4-1 is arranged at the axis position of the bevel gear 4-2, and the bevel gear 4-2 is driven to rotate forwards or backwards through the forward and reverse rotation of the motor 4-1;

teeth are arranged below the main bevel gear disc 1-2 and are meshed with the bevel gear 4-2, when the bevel gear 4-2 rotates forwards or reversely, the main bevel gear disc 1-2 is driven to rotate forwards or reversely, spiral grooves are carved on the main bevel gear disc 1-2 and are meshed with clamping grooves below the clamping jaws 1-1, and the clamping jaws 1-1 are driven to move inwards or outwards;

the clamping jaws 1-1 are arranged above the main bevel gear disc 1-2 and are circumferentially arranged, clamping grooves are carved below the clamping jaws 1-1 and are meshed with spiral grooves above the main bevel gear disc 1-2, and the clamping jaws 1-1 are driven to move inwards or outwards when the main bevel gear disc 1-2 rotates forwards or reversely;

the inner side and the outer side of the clamping jaw 1-1 are both provided with inverted teeth, and the directions of the inner side inverted teeth and the outer side inverted teeth are both inclined downwards;

the drag reduction bush 2-1 is arranged on the inner side of the main bevel gear disc 1-2, the drag reduction bush 2-1 is of an annular columnar structure, a window is arranged on the drag reduction bush and used for allowing the clamping jaw 1-1 to pass through when moving inwards, and a hemispherical ball groove is arranged on the inner side of the drag reduction bush and used for being embedded with a ball 2-2. The ball 2-2 is embedded in a ball groove on the inner side of the bushing 2-1, the diameter selection range of the ball 2-2 is 4-6 mm, and lubricating oil is filled in the ball groove on the inner side of the bushing 2-1;

the ground control mechanism 3-1 is arranged on the ground and used for transmitting an action command, and the underground receiving device 3-2 is arranged near the motor 4-1 and used for receiving the ground command and controlling the motor to act;

the upper shell 5-1 and the lower shell 5-2 are connected through bolts to achieve the fixing effect of the whole mechanism, reserved openings 5-3 are formed in the upper shell 5-1 and the lower shell 5-2 according to needs, and the reserved openings 5-3 are used for allowing the clamping jaws 1-1 to pass through outwards to clamp a well wall.

A using method of a coiled tubing conveying anti-drag device comprises the following steps;

step 1, before the coiled tubing is put in (on the ground), sleeving a coiled tubing conveying resistance reduction device on the periphery of the end part of the coiled tubing, and locking the coiled tubing by a limiting mechanism which moves inwards along the radial direction;

step 2, in the process of lowering the coiled tubing, the limiting mechanism locks the coiled tubing continuously, and the coiled tubing conveying resistance reducing device is lowered into the well along with the coiled tubing;

step 3, when the coiled tubing conveying resistance reducing device is lowered to a required depth position, the limiting device moves outwards, the coiled tubing on the inner side is loosened, and the peripheral casing/open hole well wall is clamped outwards;

step 4, anchoring the coiled tubing conveying and resistance reducing device in the fixed well depth, and converting sliding friction between the coiled tubing and the well wall into rolling friction between the coiled tubing and the resistance reducing device through the inner resistance reducing device to realize the resistance reducing function;

step 5, when the coiled tubing is pulled out, the limiting mechanism moves inwards along the radial direction, the peripheral casing pipe/open hole well wall is loosened, the coiled tubing on the inner side is locked, and the whole coiled tubing conveying resistance reducing device is pulled out together with the coiled tubing;

and 6, after the coiled tubing conveying resistance reducing device reaches the ground, the limiting mechanism moves outwards along the radial direction, the coiled tubing on the inner side is loosened, the coiled tubing can be detached from the coiled tubing, and the coiled tubing can be reused after being cleaned.

The invention has the beneficial effects that:

the coiled tubing self-locking device is put into a well along with the coiled tubing, is anchored near the self-locking point of the coiled tubing in the working process, and reduces the resistance of the coiled tubing during the putting-in process by converting the sliding friction between the coiled tubing and the casing/open hole well wall into the rolling friction between the resistance reducing mechanism and the coiled tubing, thereby preventing the self-locking phenomenon of the coiled tubing during the putting-in process.

Drawings

Fig. 1 is a schematic diagram (side view) of the main functional blocks included in the present invention.

Fig. 2 is a schematic diagram (top view) of the main functional modules included in the present invention.

FIG. 3 is a schematic representation of the preparation of the present invention prior to entering a well.

FIG. 4 is a schematic illustration of the operation of the present invention in a well.

Fig. 5 is a schematic diagram of the operation of the present invention at the point of the operating position.

Fig. 6 is a schematic diagram of the invention operating in a drag reducing state.

FIG. 7 is a schematic diagram of the operation of the recovery process of the present invention.

Fig. 8 is a schematic diagram of the invention in operation for retrieval to the surface.

FIG. 9 is a schematic representation of the removal of the present invention from coiled tubing.

Fig. 10 is a schematic sectional view of the embodiment of the present invention.

Fig. 11 is a schematic overall side view of the embodiment of the present invention.

Fig. 12 is a schematic diagram of the jaw extending and retracting state in a top view of the present invention.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings.

A coiled tubing conveying drag reduction device is installed in an annulus between a coiled tubing and a casing/open hole well wall. When in installation, the coiled tubing is put into a well together with the coiled tubing and anchored at a well body position which is most prone to buckling and self-locking; under the resistance-reducing working state, the coiled tubing can pass through the self-locking point more smoothly by utilizing rolling friction, and the possibility of buckling self-locking is reduced. The device can work at a plurality of different buckling self-locking points simultaneously.

Fig. 1 is a schematic diagram of main functional modules included in the present invention. As shown in fig. 1, the coiled tubing conveying resistance reducing device comprises five functional modules, namely a limiting mechanism 1, a resistance reducing mechanism 2, a control mechanism 3, a power mechanism 4 and a shell 5.

The limiting mechanism 1 is arranged along the radial direction of the coiled tubing conveying drag reduction device, the moving direction of the limiting mechanism is along the radial direction to move inwards or outwards, and the limiting mechanism can be locked/unlocked according to requirements after moving inwards or outwards to any position. The coiled tubing locking device has the functions of locking the coiled tubing along the radial inward movement and putting in/out together with the coiled tubing; and (3) moving outwards along the radial direction to clamp the casing/open hole well wall, releasing the coiled tubing, and anchoring the coiled tubing conveying resistance reducing device at a position where the coiled tubing is easy to self-lock. The inner side and the outer side of the limiting mechanism are respectively provided with a pawl, the pawl tooth shapes of the inner side and the outer side are both inclined downwards, and the lower pawl of the inner side of the limiting mechanism is helpful for locking the inner continuous oil pipe when the continuous oil pipe conveying resistance reducing device is lifted out; the lower helical teeth on the outer side of the limiting mechanism are beneficial to anchoring the peripheral casing/open hole well wall by the coiled tubing conveying resistance reducing device during auxiliary conveying, and displacement is prevented.

The drag reduction mechanism 2 is arranged on the inner side wall surface of the coiled tubing conveying drag reduction device and is characterized in that sliding friction between the coiled tubing and a casing/open hole well wall can be converted into rolling friction, so that conveying resistance of the coiled tubing is reduced, and the drag reduction mechanism can be a ball or a crawler. And when and only when the coiled tubing conveying resistance reducing device reaches a specified working position (self-locking point), the resistance reducing mechanism is in contact with the coiled tubing, and the sliding friction between the coiled tubing and the casing/open hole well wall is converted into the rolling friction between the resistance reducing mechanism and the coiled tubing.

The control mechanism 3 is used for receiving ground signal instructions, controlling the limiting mechanism to move inwards or outwards along the radial direction, locking the coiled tubing by moving inwards, and clamping the casing/open hole well wall by moving outwards.

The power mechanism 4 is responsible for providing power for the movement of the limiting mechanism.

The shell 5 plays a role in supporting and fixing, and the limiting mechanism, the arrowhead-shaped mechanism, the control mechanism and the power mechanism are coated into a whole on the basis that the functions of all parts are not affected.

Fig. 2-8 are schematic views of the working process of the invention.

The working process of the coiled tubing conveying resistance reducing device is as follows:

1. before the coiled tubing is put into the ground (when the coiled tubing is on the ground), the coiled tubing conveying resistance reducing device is sleeved on the periphery of the end part of the coiled tubing, and the limiting mechanism moves inwards along the radial direction to lock the coiled tubing. (FIG. 3)

2. In the process of lowering the coiled tubing, the limiting mechanism locks the coiled tubing continuously, and the coiled tubing conveying resistance reducing device is lowered into the well along with the coiled tubing. (FIG. 4)

3. When the coiled tubing conveying resistance reducing device is lowered to a required depth position, the limiting device moves outwards, the coiled tubing on the inner side is loosened, and the peripheral casing/open hole well wall is clamped outwards. (FIG. 5)

4. The coiled tubing conveying and drag reducing device is anchored in the depth of the fixed well, and the sliding friction between the coiled tubing and the well wall is converted into the rolling friction between the coiled tubing and the drag reducing device through the inner drag reducing device, so that the drag reducing function is realized. (FIG. 6)

5. When the coiled tubing is pulled out, the limiting mechanism moves inwards along the radial direction, the peripheral casing/open hole well wall is loosened, the coiled tubing on the inner side is locked, and the whole coiled tubing conveying resistance reducing device is pulled out together with the coiled tubing. (FIG. 7)

6. After the coiled tubing conveying resistance reducing device reaches the ground, the limiting mechanism moves outwards in the radial direction, the coiled tubing on the inner side is loosened, the coiled tubing can be detached from the coiled tubing, and the coiled tubing conveying resistance reducing device can be repeatedly used after being cleaned. (FIG. 8, FIG. 9)

The present invention will be described in further detail with reference to the following application examples.

The application case comprises five parts, namely a limiting mechanism 1, a resistance reducing mechanism 2, a control mechanism 3, a power mechanism 4 and a shell 5.

The limiting mechanism 1 comprises a claw 1-1 and a main bevel gear disc 1-2.

The drag reduction mechanism 2 comprises a drag reduction bush 2-1 and drag reduction balls 2-2.

The control mechanism 3 comprises a surface control device 3-1 and a downhole receiving device 3-2.

The power mechanism 4 comprises a motor 4-1 and a bevel gear 4-2.

The shell 5 comprises an upper shell 5-1 and a lower shell 5-2.

The motor 4-1 is arranged at the axis position of the bevel gear 4-2, and the bevel gear 4-2 is driven to rotate forwards or backwards through the forward and reverse rotation of the motor 4-1.

Teeth are arranged below the main bevel gear disc 1-2 and are meshed with the bevel gear 4-2, and when the bevel gear 4-2 rotates forwards or reversely, the main bevel gear disc 1-2 can be driven to rotate forwards or reversely. A spiral groove is carved on the upper part of the main bevel gear disc 1-2 and is meshed with a clamping groove on the lower part of the clamping jaw 1-1 to drive the clamping jaw 1-1 to move inwards or outwards.

The clamping jaws 1-1 are arranged above the main bevel gear disc 1-2, and a plurality of clamping jaws are arranged along the circumferential direction. A clamping groove is formed in the lower portion of the clamping jaw 1-1 and meshed with the spiral groove in the upper portion of the main bevel gear disc 1-2, when the main bevel gear disc 1-2 rotates forwards or reversely, the clamping jaw 1-1 is driven to move inwards or outwards, and an inner oil pipe is tightly held or a peripheral well wall is clamped according to application requirements.

The inner side and the outer side of the clamping jaw 1-1 are both provided with inverted teeth, and the directions of the inner side inverted teeth and the outer side inverted teeth are both inclined downwards. When the clamping jaws tightly hold the inner side oil pipe and go into a well, once the clamping jaws are blocked, the inverted teeth with the inner side inclined downwards enable the continuous oil pipe conveying resistance reducing device not to easily slip off and displace from the central pipe; when the claw clamps the peripheral well wall and is in drag reduction work, the peripheral downward-inclined inverted teeth lock the continuous oil pipe conveying drag reduction device, so that the continuous oil pipe conveying drag reduction device is not easy to slide and displace downwards.

The drag reduction bush 2-1 is arranged on the inner side of the main bevel gear disc 1-2. The resistance-reducing bush 2-1 is of an annular columnar structure, and a window is arranged on the resistance-reducing bush and is used for the claw 1-1 to pass through when moving inwards. The inner side of the drag reduction bush is provided with a hemispherical ball groove for embedding the ball 2-2. The ball 2-2 is embedded in the ball groove at the inner side of the bush 2-1. The diameter of the ball 2-2 is selected to be 4-6 mm. Lubricating oil is filled in a ball groove on the inner side of the bushing 2-1, and the lubricating oil is fully contacted with the balls under the continuous rolling of the balls, so that the rolling friction of the continuous oil pipe when the continuous oil pipe passes through a buckling point is further reduced.

The ground control mechanism 3-1 is arranged on the ground and used for transmitting action instructions. The underground receiving device 3-2 is arranged near the motor 4-1 and used for receiving ground instructions and controlling the motor to act.

The upper shell 5-1 and the lower shell 5-2 are an upper part and a lower part of the shell 5, and the upper shell 5-1 and the lower shell 5-2 are connected through bolts to realize the fixing function of the whole mechanism. Reserved openings 5-3 are formed in the upper shell 5-1 and the lower shell 5-2 according to needs, and the reserved openings 5-3 are used for allowing the clamping jaws 1-1 to pass through outwards to clamp a well wall.

The working process of the application case of the coiled tubing conveying resistance reducing device comprises the following steps:

1. before running the coiled tubing in (at the surface), the coiled tubing is passed through the middle prepared hole of the application case device. The control equipment 3-1 sends an electronic instruction for enabling the motor 4-1 to rotate forwards, the underground receiving device 3-2 receives the electronic instruction and controls the motor 4-1 to start the forward rotation. The motor 4-1 rotates forwards to drive the bevel gear shaft 4-2 to rotate clockwise, the main bevel gear disc 1-2 matched with the bevel gear shaft rotates clockwise, the claw 1-1 is driven to move inwards through the spiral groove on the surface layer of the main bevel gear disc 1-2, and the motor 4-1 stops rotating after the coiled tubing is locked.

2. In the process of putting the coiled tubing in, the clamping jaw 1-1 locks the coiled tubing continuously, and the application case device is put into the well together with the coiled tubing.

3. When the coiled tubing conveying resistance reducing device is lowered to a required depth position, the ground control equipment 3-1 sends an electronic instruction for enabling the motor 4-1 to rotate reversely, and the underground receiving device 3-2 receives the electronic instruction and controls the motor 4-1 to rotate reversely. The motor 4-1 rotates reversely to drive the bevel gear 4-2 to rotate anticlockwise, the main bevel gear disc 1-2 matched with the bevel gear disc rotates anticlockwise, the claw 1-1 is driven to move outwards through the spiral groove in the surface layer of the main bevel gear disc 1-2, and the motor 4-1 stops rotating after the coiled tubing is loosened and the peripheral well wall is clamped.

4. In the resistance reducing working process of the continuous oil pipe, the continuous oil pipe conveying resistance reducing device is anchored at a specified depth position, sliding friction between the continuous oil pipe and a well wall is converted into rolling friction between the continuous oil pipe and the resistance reducing device through the inner side balls 2-2, and the resistance reducing function is achieved.

5. When the coiled tubing is pulled out, the ground control equipment 3-1 sends an electronic instruction for enabling the motor 4-1 to rotate forwards, and the underground receiving device 3-2 receives the electronic instruction and controls the motor 4-1 to rotate forwards. The motor 4-1 rotates forwards to drive the bevel gear 4-2 to rotate clockwise, the main bevel gear disc 1-2 matched with the bevel gear disc rotates clockwise, the claw 1-1 is driven to move inwards through the spiral groove on the surface layer of the main bevel gear disc 1-2, and the motor 4-1 stops rotating after the peripheral well wall is loosened and the coiled tubing is tightly held. The application case device is lifted out together with the coiled tubing.

6. After the coiled tubing conveying resistance reducing device reaches the ground, the ground control equipment 3-1 sends an electronic instruction for enabling the motor 4-1 to rotate reversely, and the underground receiving device 3-2 receives the electronic instruction and controls the motor 4-1 to rotate reversely. The motor 4-1 rotates reversely to drive the bevel gear 4-2 to rotate anticlockwise, the main bevel gear disc 1-2 matched with the bevel gear disc rotates anticlockwise, the claw 1-1 is driven to move outwards through the spiral groove in the surface layer of the main bevel gear disc 1-2, and after the coiled tubing is loosened, the motor 4-1 stops rotating. And disassembling the application case device from the coiled tubing, and cleaning the application case device for reuse.

Claims

1. a coiled tubing transport drag reduction device, is characterized in that, the coiled tubing transport drag reduction device comprises a limiting mechanism, a drag reduction mechanism, a control mechanism, a power mechanism and a casing;

The coiled tubing transport drag reduction device is installed in the annulus between the coiled tubing and the casing/open hole wall. During installation, the coiled tubing is run into the well together with the coiled tubing. Under the working condition of drag reduction, it is anchored at the self-locking point of the coiled tubing. nearby;

The limiting mechanism is used to move the coiled tubing radially inward to lock the coiled tubing, and run in/out together with the coiled tubing;

The drag reduction mechanism is used to convert the sliding friction between the coiled tubing and the casing/open hole wall into rolling friction;

The control mechanism is responsible for receiving ground signal instructions, and controls the limit mechanism to move radially inward or outward, move inward to lock the coiled tubing, and move outward to block the casing/open hole wall;

The power mechanism is responsible for providing the power for the movement of the limit mechanism;

The casing covers the limiting mechanism, the drag reduction mechanism, the control mechanism and the power mechanism as a whole.

2 . The coiled tubing transportation drag reduction device according to claim 1 , wherein the limiting mechanism is radially arranged along the coiled tubing transportation drag reduction device, and its movement direction is radially inward or outward. 3 . After moving inward or outward to any position, it can be locked/unlocked according to requirements, and the casing/open hole wall can be stuck by moving outward in the radial direction. At the same time, the coiled tubing is released, and the coiled tubing is transported to the drag reduction device. It is anchored in the position where the downhole coiled tubing is prone to self-locking.

3 . The coiled tubing conveying drag reduction device according to claim 1 , wherein the inner and outer ends of the limiting mechanism are provided with inverted teeth, and the inner and outer inverted teeth are inclined downward, limiting the limit. 4 . The lower helical teeth on the inner side of the positioning mechanism help the coiled tubing to lock the inner coiled tubing when the coiled tubing transportation drag reduction device is pulled out; the lower helical teeth on the outer side of the limit mechanism help the coiled tubing transportation drag reduction device to anchor during auxiliary transportation. Set the peripheral casing/open hole wall to prevent displacement.

4 . The coiled tubing transportation drag reduction device according to claim 1 , wherein the drag reduction mechanism is arranged on the inner wall surface of the coiled tubing transportation drag reduction device to reduce the coiled tubing transportation resistance. The drag mechanism is a ball or crawler, and the coiled tubing conveying drag reduction device starts to work if and only when the coiled tubing conveying drag reduction device reaches the designated working position (self-locking point), at which time the drag reduction mechanism contacts the coiled tubing, connecting the coiled tubing to the casing/open hole The sliding friction between the well walls is converted into the rolling friction between the drag reducing mechanism and the coiled tubing.

5 . The coiled tubing transportation drag reduction device according to claim 1 , wherein the casing plays a supporting and fixing role. 6 .

6. The coiled tubing conveying drag reduction device according to claim 1, wherein the limiting mechanism comprises a clamping claw (1-1) and a main bevel gear plate (1-2);

The drag reduction mechanism includes a drag reduction bush (2-1) and a drag reduction ball (2-2);

The control mechanism includes ground control equipment (3-1) and a downhole receiving device (3-2);

The power mechanism includes a motor (4-1) and a bevel gear (4-2);

The casing includes an upper casing (5-1) and a lower casing (5-2);

The motor (4-1) is installed at the axis of the bevel gear (4-2), and the bevel gear (4-2) is driven to rotate forward or reverse by the forward and reverse rotation of the motor (4-1);

There are teeth under the main bevel gear plate (1-2), which mesh with the bevel gear (4-2). When the bevel gear (4-2) rotates forward or reverse, it drives the main bevel gear plate (1-2) to the forward Or reverse rotation, the top of the main bevel gear plate (1-2) is engraved with a spiral groove, which meshes with the lower groove of the claw (1-1), and drives the claw (1-1) to move inward or outward;

The clamping claw (1-1) is arranged above the main bevel gear plate (1-2), and several are arranged in the circumferential direction, and a clamping groove is engraved under the clamping claw (1-1), and the clamping groove is connected to the main bevel gear plate (1-1). -2) The upper spiral groove meshes, and when the main bevel gear plate (1-2) rotates forward or reverse, it drives the jaws (1-1) to move inward or outward;

The inner and outer sides of the jaws (1-1) are provided with inverted teeth, and the directions of the inner and outer inverted teeth are inclined downward;

The drag reduction bushing (2-1) is arranged on the inner side of the main bevel gear disc (1-2), and the drag reduction bushing (2-1) is an annular columnar structure, and windows are arranged on it for the clamping jaws (1- 1) When passing inward, a hemispherical ball groove is arranged on the inside of the drag reducing bush for inserting the ball (2-2), and the ball (2-2) is embedded in the ball groove on the inside of the bush (2-1). , the diameter of the ball (2-2) is selected in the range of 4 to 6mm, and the ball groove inside the bushing (2-1) is filled with lubricating oil;

The ground control mechanism (3-1) is arranged on the ground for transmitting action commands, and the downhole receiving device (3-2) is arranged near the motor (4-1) for receiving ground commands and controlling the action of the motor;

The upper casing (5-1) and the lower casing (5-2) are connected by bolts to realize the fixing function of the whole mechanism. A reserved opening (5-3) is provided, and the reserved opening (5-3) is used for the clamping claw (1-1) to pass outwards and jam the well wall.

7. A method for using a coiled tubing transport drag reduction device according to any one of claims 1-6, characterized in that, comprising the following steps;

Step 1. Before the coiled tubing is lowered (when it is on the ground), the coiled tubing transportation drag reduction device is sleeved on the periphery of the end of the coiled tubing, and the limit mechanism moves inward in the radial direction to lock the coiled tubing;

Step 2. During the running of the coiled tubing, the limiting mechanism continues to lock the coiled tubing, and the coiled tubing transportation drag reduction device is lowered into the well together with the coiled tubing;

Step 3. When the coiled tubing transportation drag reduction device is lowered to the required depth, the limiting device moves outwards, loosens the inner coiled tubing, and clamps the outer casing/open hole wall outwards;

Step 4. The coiled tubing transport drag reduction device is anchored at the depth of the fixed well, and the sliding friction between the coiled tubing and the well wall is converted into the rolling friction between the coiled tubing and the drag reduction device through the inner drag reduction device to achieve drag reduction Function;

Step 5. When the coiled tubing is pulled out, the limiting mechanism moves radially inward, loosens the outer casing/open hole wall, locks the inner coiled tubing, and the entire coiled tubing transportation drag reduction device is pulled out together with the coiled tubing;

Step 6. After the coiled tubing conveying drag reduction device reaches the ground, the limit mechanism moves outward in the radial direction, loosening the inner coiled tubing, it can be disassembled from the coiled tubing, and can be reused after cleaning.