Coiled tubing assembly for increasing tripping-in depth of coiled tubing in horizontal well or inclined well

Abstract

The invention provides a coiled tubing assembly for increasing the tripping-in depth of a coiled tubing in a horizontal well or an inclined well, and relates to the technical field of coiled tubing operation. Comprising an operation vehicle for conveying the coiled tubing into a shaft, the coiled tubing capable of being conveyed into the shaft, a plurality of sets of rotating assemblies installed at the tail end of the coiled tubing, and operation tool assemblies installed at the tail ends of the rotating assemblies and used for downhole operation, so that the risk of bending or self-locking of the coiled tubing is reduced. The problem that the tripping-in depth of the continuous pipe in a horizontal well or an inclined well cannot meet the operation requirement is solved, and meanwhile the safety of field operation is improved.

Description

Technical Field

[0001] The invention relates to the technical field of coiled tubing operations, and in particular to a coiled tubing assembly for increasing the depth of a coiled tubing in a horizontal well or an inclined well. Background Art

[0002] Due to the characteristics of the coiled tubing, such as light weight, low stiffness, large deflection, and small radial size, in "non-vertical" wells, due to the curvature and azimuth changes of the horizontal wellbore trajectory, the coiled tubing will encounter greater resistance during operation, and the depth of the coiled tubing will be seriously affected, which will directly lead to reduced construction efficiency and even failure to reach the operating depth. According to research, when the coiled tubing is "pushed" from the ground position to the wellbore, when the coiled tubing enters the non-vertical section of the wellbore, a large annular gap will be formed between the wellbore and the coiled tubing. Under the constraint of the wellbore wall, the coiled tubing rubs against the inner wall of the wellbore under the action of axial force, thereby generating friction resistance. As the length of the horizontal section of the coiled tubing increases, the friction resistance between it and the inner wall of the wellbore also increases accordingly, and the coiled tubing begins to bend at one or more points. The coiled tubing deforms into a sine wave in the wellbore. When the load increases further, the pipe string gradually presents a "spiral" effect of three-dimensional buckling from sinusoidal buckling. As the buckling further develops, the pipe string contacts the inner wall of the wellbore at multiple points, and the spiral buckling will eventually lead to spiral "self-locking". Once the tubing self-locks, the axial load cannot be effectively transmitted and the coiled tubing assembly can no longer be pushed further into the wellbore. This has become a key factor restricting the coiled tubing construction process.

[0003] Reducing friction is an effective way to increase the depth of coiled tubing. The hydraulic oscillators and metal drag-reducing agents currently used are used to increase the depth of coiled tubing by reducing the friction coefficient. However, with the rapid increase in the number and length of horizontal wells in my country, the friction between the coiled tubing and the wellbore wall has increased. The existing hydraulic oscillators and metal drag-reducing agents still cannot meet the operational requirements, limiting the depth of coiled tubing in "non-vertical" wells and affecting the subsequent oil and gas reservoir transformation effect.

[0004] Therefore, it is urgent to solve the above problems. A method is needed to reduce the risk of coiled tubing bending or self-locking, further increase the running depth of the coiled tubing in a horizontal well or an inclined well, and improve the safety of field operations. Summary of the invention

[0005] The object of the present invention is to provide a coiled tubing assembly for increasing the depth of the coiled tubing in a horizontal well or an inclined well, so as to reduce the risk of bending or self-locking of the coiled tubing, overcome the problem that the depth of the coiled tubing in the horizontal well or the inclined well cannot meet the operation requirements, and at the same time improve the safety of field operations.

[0006] Implementation of the present invention: A coiled tubing assembly for increasing the depth of a coiled tubing in a horizontal well or an inclined well, comprising an operation vehicle for conveying the coiled tubing into a wellbore, the coiled tubing that can be conveyed into the wellbore, a plurality of rotating assemblies installed at the end of the coiled tubing, and an operation tool assembly installed at the end of the rotating assembly; The rotating assembly includes a rotating connection device, a rotating device, an emergency separation device and a rotating pipe string; the rotating device is connected to the continuous pipe through the rotating connection device; the rotating device is connected to the rotating pipe string through the emergency separation device; the end of the rotating pipe string is connected to the working tool assembly through the one-way rotating device; The outer surface of the rotating column is provided with a plurality of ball grooves; a ball cover plate is provided outside the ball groove; balls are provided between the ball groove and the ball cover plate; and a plurality of rotating components are connected by a continuous pipe.

[0007] The ball is made of sacrificial anode material and is corroded first in the underground corrosive environment, thereby protecting other parts of the coiled tubing assembly from corrosion in the underground environment and increasing the service life of the coiled tubing assembly.

[0008] Several groups of rotating components are connected by continuous pipes.

[0009] Beneficial effects of the present invention: 1. During the process of going down the well, the rotating device can apply torque to the rotating tubing string and make the rotating tubing string rotate relative to the coiled tubing. By rotating the tubing string, the process of the coiled tubing going down the well changes from a sliding state to a combined rotation and sliding motion, and the friction condition between the coiled tubing in the well and the inner wall of the wellbore changes from a static friction state to a dynamic friction state, which reduces the friction resistance of the coiled tubing, significantly improves the extension capacity of the coiled tubing in the wellbore, reduces the risk of coiled tubing bending or self-locking, and improves the safety of field operations; 2. The emergency separation tool can prevent the coiled tubing from being twisted off. When the rotating tubing string generates excessive counter torque and reaches the preset torque limit of the coiled tubing, the emergency separation tool will be separated from the upper end rotating device; 3. Wear-resistant balls are designed on the outer surface of the rotating tubing string to further reduce the friction between the rotating tubing string and the wellbore. At the same time, the balls are made of sacrificial anode material and are corroded first in the underground corrosive environment, thereby protecting other parts of the coiled tubing assembly from corrosion in the underground environment. The service life of the rotating tubing string can be extended by replacing the balls. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 This is a schematic diagram of the continuous tube assembly described in Example 1; Figure 2 This is a schematic diagram of the rotating assembly described in Example 1; Figure 3 This is a schematic diagram of the rotating column described in Example 1; Figure 4 This is a schematic diagram of the rotating assembly described in Example 2; In the figure, 1 is an operation vehicle, 2 is a continuous pipe, 2-1 is a wellbore, 3 is a rotating assembly, 3-1 is a rotating connection device, 3-2 is a rotating device, 3-3 is an emergency separation device, 3-4 is a rotating pipe string, 3-4-1 is a ball groove, 3-4-2 is a ball cover plate, 3-4-3 is a ball, 3-5 is a single rotating device, and 4 is an operation tool assembly. Implementation

[0011] The present invention is further described below through specific implementation examples. Example 1

[0012] This embodiment provides a coiled tubing assembly for increasing the depth of a coiled tubing in a horizontal well or a deviated well, comprising a work vehicle 1 for conveying a coiled tubing 2 into a wellbore 2-1, a coiled tubing 2 that can be conveyed into the wellbore 2-1, a set of rotating assemblies 3 installed at the end of the coiled tubing 2, and an operating tool assembly 4 installed at the end of the rotating assembly 3; The rotating assembly 3 includes a rotating connection device 3-1, a rotating device 3-2, an emergency separation device 3-3 and a rotating pipe string 3-4; the rotating device 3-2 is connected to the coiled pipe 2 through the rotating connection device 3-1; the rotating device 3-2 is connected to the rotating pipe string 3-4 through the emergency separation device 3-3, and the emergency separation device 3-3 can be separated from the rotating pipe string 3-4 when the rotating pipe string 3-4 generates excessive counter torque and reaches the torque limit of the coiled pipe 2, so as to prevent the coiled pipe from being twisted off; the end of the rotating pipe string 3-4 is connected to the working tool assembly 4 through the one-way rotating device 3-5, and the one-way rotating device 3-5 can make the rotating pipe string 3-4 rotate in one angular direction relative to the coiled pipe 2, but cannot rotate in the opposite angular direction; The outer surface of the rotating column 3-4 is provided with a plurality of ball grooves 3-4-1; a ball cover plate 3-4-2 is provided outside the ball groove 3-4-1; a ball 3-4-3 is provided between the ball groove 3-4-1 and the ball cover plate 3-4-2; The ball 3-4-3 is made of sacrificial anode material, which is corroded first in the underground corrosive environment, thereby protecting other parts of the coiled tubing assembly from corrosion in the underground environment and increasing the service life of the coiled tubing assembly.

[0013] In this embodiment: The rotary connection device 3-1 is a slip connector produced by Siji Saiwa Oil Drilling Equipment Co., Ltd., with the part number: D97-1150-162; The rotating device 3-2 is a Weatherford CTD hydraulic screw motor; The emergency separation device 3-3 is a hydraulic release joint produced by Siji Saiwa Petroleum Drilling Equipment Co., Ltd., with the product number: D97-1212-503. Example 2

[0014] This embodiment provides a coiled tubing assembly for increasing the depth of a coiled tubing in a horizontal well or a deviated well, and is different from the embodiment 1 in that two sets of rotating assemblies 3 are installed at the end of the coiled tubing 2; The rotating pipe column 3-4 at the end of the first rotating assembly 5-1 is connected to the rotating connection device 3-1 of the second rotating assembly 5-2 through the second continuous pipe 5-3.

[0015] The above contents are further detailed descriptions of the present invention in combination with specific preferred embodiments, and the specific implementation of the present invention cannot be limited to these descriptions. For ordinary technicians in the field to which the present invention belongs, several simple deductions or substitutions can be made without departing from the concept of the present invention, which should be regarded as falling within the protection scope of the present invention.

Claims

1. A coiled tubing assembly for increasing the depth of a coiled tubing in a horizontal well or a deviated well, characterized in that: It comprises an operation vehicle (1) for conveying a coiled tubing (2) into a wellbore (2-1), a coiled tubing (2) that can be conveyed into the wellbore (2-1), a plurality of groups of rotating assemblies (3) installed at the end of the coiled tubing (2), and an operation tool assembly (4) installed at the end of the rotating assembly (3); The rotating assembly (3) comprises a rotating connection device (3-1), a rotating device (3-2), an emergency separation device (3-3) and a rotating pipe column (3-4); The rotating device (3-2) is connected to the continuous tube (2) via a rotating connecting device (3-1); The rotating device (3-2) is connected to the rotating pipe column (3-4) via an emergency separation device (3-3); The end of the rotating pipe string (3-4) is connected to the working tool assembly (4) via a one-way rotating device (3-5); The outer surface of the rotating column (3-4) is provided with a plurality of ball grooves (3-4-1); A ball cover plate (3-4-2) is provided outside the ball groove (3-4-1); A ball (3-4-3) is provided between the ball groove (3-4-1) and the ball cover plate (3-4-2); The plurality of groups of rotating components (3) are connected via a continuous pipe (2).

2. The coiled tubing assembly for increasing the depth of a coiled tubing in a horizontal well or a deviated well according to claim 1, characterized in that: The material of the ball (3-4-3) is sacrificial anode material.

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