A downhole throttling process pipe string and method for horizontal wells

Abstract

The present invention discloses a downhole throttling process string and method for a horizontal well, including a downhole throttling device setting process string and a downhole throttling device drilling and grinding process string; the downhole throttling device setting process string includes a first continuous oil pipe, one end of the continuous oil pipe extending into the horizontal well is connected to a first double-flap check valve through a first connector, the free end of the first double-flap check valve is connected to a first shear release hand, the free end of the first shear release hand is connected to a hydraulic delivery tool, and the free end of the hydraulic delivery tool is connected to a downhole throttling device; the downhole throttling device drilling and grinding process string includes a second double-flap check valve connected to the end of the second continuous oil pipe through a second connector, the free end of the second double-flap check valve is connected to a second shear release hand, the free end of the second shear release hand is connected to a screw drill through a circulation joint, and the free end of the screw drill is connected to a drill bit. The present invention can be installed at any position of the horizontal section as needed to ensure that the downhole throttling of the horizontal well achieves the best effect.

Description

Technical Field

[0001] The invention relates to a downhole process pipe column for throttling and reducing pressure in a natural gas production process, which is suitable for use in a gas well horizontal well with self-flowing capability. Background Art

[0002] Horizontal wells have unparalleled advantages over conventional vertical wells in terms of technology and economic benefits. With the development of drilling and oil (gas) production technology, horizontal wells have been widely used in the development of gas reservoirs. When gas well production enters the middle and late stages, the wellbore liquid accumulation intensifies, and drainage gas production is an effective way to solve the problem of gas well liquid accumulation. Downhole throttling technology is a process technology that allows the throttling and pressure reduction process of natural gas to occur in the wellbore of the gas well through a downhole throttle. It is a drainage gas production technology with the advantages of good drainage and gas production effect, simple operation, and low cost. Therefore, it is widely used in gas well production. Due to the limitations of existing process conditions, the downhole throttle of gas wells is currently limited to installation in the wellbore of the vertical well section, and the scope of influence is limited. As the horizontal section lengthens, the drainage and gas production effect of the downhole throttle decreases exponentially, especially in the middle and late stages of development when the water production is large, it has almost no effect. Summary of the invention

[0003] The purpose of the present invention is to provide a downhole throttling process string and method for a horizontal well, so as to solve the disadvantage that conventional downhole throttling devices can only be installed in vertical well sections. The present invention can be installed at any position in the horizontal section as required to ensure that the downhole throttling of the horizontal well achieves the best effect.

[0004] In order to achieve the above object, the present invention adopts the following technical scheme:

[0005] A downhole choke process string for a horizontal well, comprising a downhole choke setting process string when setting a downhole choke and a downhole choke drilling and grinding process string when pulling out a downhole choke;

[0006] The downhole choke setting process string comprises a first coiled tubing arranged on a coiled tubing operation machine, one end of the first coiled tubing extending into the horizontal well is connected to a first double-flap check valve through a first connector, a free end of the first double-flap check valve is connected to a first shear release hand, a free end of the first shear release hand is connected to a hydraulic delivery tool, and a free end of the hydraulic delivery tool is connected to a downhole choke;

[0007] The downhole throttle drilling and grinding process string includes a second continuous tubing arranged on a continuous tubing operation machine, the end of the second continuous tubing is connected to a second double-flap check valve through a second connector, the free end of the second double-flap check valve is connected to a second shear release hand, the free end of the second shear release hand is connected to a screw drill through a circulation joint, and the free end of the screw drill is connected to a drill bit.

[0008] A downhole throttling method for a horizontal well, comprising a setting process and a drilling and grinding process;

[0009] The sealing process is specifically as follows: firstly, a well cleaning operation is performed, and then the first connector is connected to the end of the first coiled tubing, and the first double-flap check valve, the first shear release hand, the hydraulic delivery tool and the downhole choke are sequentially connected to the first connector, and the first connector, the first double-flap check valve, the first shear release hand, the hydraulic delivery tool and the downhole choke are used as a downhole tool string, and after the downhole tool string is lowered into place, a ball corresponding to the hydraulic delivery tool is dropped, and when the ball falls on the hydraulic delivery tool, hydraulic pressure is added to 20MPa from the first coiled tubing to achieve the downhole choke release hand and sealing;

[0010] The drilling and grinding process is as follows: first, the well cleaning operation is carried out, and then the downhole choke drilling and grinding process string is lowered to a distance of 1m-2m from the downhole choke, and 0.2-0.3m is injected from the second coiled tubing. 3 The displacement is used to drive the screw drill bit to work, and the downhole choke drilling and grinding process pipe string is lowered. After flushing the surface of the downhole choke, the drilling pressure is controlled to 5kN-15kN until the downhole choke is released.

[0011] Compared with the prior art, the present invention has the following beneficial technical effects:

[0012] The present invention adopts the method of dragging the downhole choke by continuous oil tubing to replace the conventional steel wire to drag the downhole choke, so that the downhole choke can be lowered to any position of the horizontal section to achieve the best downhole throttling effect. After the downhole choke is dragged to the specified position by the continuous oil tubing, the downhole choke is sealed by hydraulic method. The tool string has a simple structure and reliable sealing. When the downhole choke needs to be released, it does not need to be salvaged, and only the drilling and grinding process pipe string needs to be lowered to drill and grind the downhole choke to release it. The releasing method is safe and reliable. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a schematic diagram of the structure of the downhole throttling process string of a horizontal well;

[0014] Figure 2 This is a schematic diagram of the tubing structure for the downhole throttle drilling and grinding process.

[0015] In the figure, 1. a first continuous tubing, 2. a first connector, 3. a first double-flap check valve, 4. a first shear release, 5. a hydraulic delivery tool, 6. a downhole choke, 7. a second continuous tubing, 8. a second connector, 9. a second double-flap check valve, 10. a second shear release, 11. a circulation joint, 12. a screw drill, and 13. a drill bit. DETAILED DESCRIPTION

[0016] The present invention is further described in detail below in conjunction with the accompanying drawings:

[0017] See also Figure 1 and Figure 2 The horizontal well downhole throttling process string used in the present invention includes a downhole throttling setting process string when setting the downhole throttling and a downhole throttling drilling process string when pulling out the downhole throttling. The downhole throttling setting process string includes a first continuous oil pipe 1, a first connector 2, a first double-flap check valve 3, a first shear release 4, a hydraulic delivery tool 5, and a downhole throttling 6. The first continuous oil pipe 1 is connected to the first double-flap check valve 3 through the first connector 2, and a hydraulic pressure relief valve 5 is connected at the lower end of the first double-flap check valve 3. A first shear release 4, the lower end of which is connected to a hydraulic delivery tool 5, the lower end of which is connected to a downhole choke 6; the downhole choke drilling and grinding process string of the present invention comprises a second double-flap check valve 9 connected to the end of a second continuous tubing 7 through a second connector 8, the free end of the second double-flap check valve 9 is connected to a second shear release 10, the free end of the second shear release 10 is connected to a screw drill 12 through a circulation joint 11, and the free end of the screw drill 12 is connected to a drill bit 13.

[0018] The present invention is described in detail below in conjunction with embodiments:

[0019] See also Figure 1 and Figure 2 The use process of the horizontal well downhole throttling process string is as follows:

[0020] 1. Sealing

[0021] Perform well cleaning operations to ensure that the wellbore is clean; connect the assembled downhole choke 6 to the hydraulic delivery tool string of the coiled tubing. The downhole tool string from top to bottom is: the first connector 2+the first double-flap check valve 3+the first shear release 4+the hydraulic delivery tool 5+the downhole choke 6. After the tool string is in place, throw the ball corresponding to the hydraulic delivery tool. When the ball falls on the hydraulic delivery tool 5, the hydraulic pressure is added to 20MPa from the coiled tubing to achieve the downhole choke 6 release and sealing.

[0022] 2. Drilling and grinding

[0023] When it is necessary to release the downhole choke, perform well cleaning operations; lower the downhole choke drilling and grinding process string to 1m-2m of the downhole choke, and inject 0.2-0.3m from the coiled tubing 3 The displacement is used to drive the screw drill to drive the drill bit to work, and the downhole choke drilling and grinding process pipe string is lowered. After flushing the surface of the downhole choke 6, the drilling pressure is controlled to 5kN-15kN until the downhole choke is released.

Claims

1. A downhole throttling method for a horizontal well, characterized in that: A downhole throttling process string for a horizontal well is used, including a downhole throttling setting process string when setting the downhole throttling device and a downhole throttling drilling process string when pulling out the downhole throttling device; The downhole choke setting process string comprises a first coiled tubing (1) arranged on a coiled tubing operation machine, one end of the first coiled tubing (1) extending into the horizontal well is connected to a first double-flap check valve (3) via a first connector (2), the free end of the first double-flap check valve (3) is connected to a first shear release hand (4), the free end of the first shear release hand (4) is connected to a hydraulic delivery tool (5), and the free end of the hydraulic delivery tool (5) is connected to a downhole choke (6); The downhole choke drilling and grinding process string comprises a second coiled tubing (7) arranged on a coiled tubing operation machine, the end of the second coiled tubing (7) is connected to a second double-flap check valve (9) via a second connector (8), the free end of the second double-flap check valve (9) is connected to a second shear release hand (10), the free end of the second shear release hand (10) is connected to a screw drill (12) via a circulation joint (11), and the free end of the screw drill (12) is connected to a drill bit (13); The horizontal well downhole throttling method includes a setting process and a drilling and grinding process; The sealing process is specifically as follows: firstly, a well cleaning operation is performed, and then the first connector (2) is connected to the end of the first coiled tubing (1), and the first double-flap check valve (3), the first shear release hand (4), the hydraulic release tool (5) and the downhole choke (6) are sequentially connected to the first connector (2), and the first connector (2), the first double-flap check valve (3), the first shear release hand (4), the hydraulic release tool (5) and the downhole choke (6) are used as a downhole tool string. After the downhole tool string is lowered into place, a ball corresponding to the hydraulic release tool is released, and when the ball falls onto the hydraulic release tool (5), hydraulic pressure is added to 20 MPa from the first coiled tubing (1), so that the downhole choke (6) is released and the sealing is achieved; The drilling and grinding process is specifically as follows: firstly, a well cleaning operation is performed, then a downhole choke drilling and grinding process string is lowered to a distance of 1m-2m from the downhole choke (6), and 0.2-0.3m is injected from the second coiled tubing (7). 3 The displacement is used to drive the screw drill (12) to drive the drill bit (13) to work, and the downhole choke drilling and grinding process pipe string is lowered to flush the surface of the downhole choke (6). The drilling pressure is controlled to 5kN-15kN until the downhole choke (6) is released.

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