Liner tube feeding device and liner tube feeding method for horizontal drill hole under pressure

Abstract

The invention relates to a liner tube feeding device and a liner tube feeding method for a horizontal drill hole under pressure. The liner tube feeding device comprise a plurality of liner tubes, a plurality of drill rods and an orifice pressure-maintaining device for the horizontal drill hole, wherein matched screw threads are arranged at the two ends of the liner tubes; the inner diameter of each liner tube is larger than the outer diameter of each drill rod; the orifice pressure-maintaining device is provided with a liner tube channel suitable for the liner tubes to insert and penetrate through, and comprises a three-way pipe short section, a gate valve, a first liner tube clamper, a blowout preventer, a first barrel, a second barrel, a second liner tube clamper and a ring-shaped sealerconnected sequentially from front to back; the first barrel is in threaded connection with the second barrel; and a screw-thread buckle type between the first barrel and the second barrel is the sameas a screw-thread buckle type between the two liner tubes in threaded connection. Through the liner tube feeding device and the liner tube feeding method for the horizontal drill hole under pressureprovided by the invention, the liner tubes can be sequentially connected and fed into the horizontal drill hole under pressure, and the liner tubes located in the drill hole can completely eradicate the occurrence of the phenomenon that collapsing holes block the drill hole, so that the long-time safety and unobstruction of a gas production channel of the drill hole is ensured, and the continuousstability of the coalbed gas extraction rate is ensured.

Description

technical field [0001] The invention relates to a liner pipe feeding device and a liner pipe feeding method for pressurized horizontal drilling, belonging to the fields of horizontal drilling and coal bed gas exploitation. Background technique [0002] When mining coalbed methane in coal mine roadways, horizontal drilling is usually used, and the drilling methods are mainly divided into normal pressure drilling and pressure drilling. [0003] In some areas of my country, such as Yunnan, Guizhou and other coal-producing areas, the coal quality is relatively soft and the ground stress is relatively large. After the final hole exits the drilling tool, large-scale collapse and slag will occur in the hole within a short period of time. The borehole was completely blocked, resulting in a rapid decline in the extraction volume of coalbed methane, and the original planned extraction target could not be achieved. For coal seams with soft coal quality, drilling under pressure is easie...

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Problems solved by technology

[0003] In some areas of my country, such as Yunnan, Guizhou and other coal-producing areas, the coal quality is relatively soft and the ground stress is relatively large. After the final hole exits the drilling tool, large-scale collapse and slag will occur in the hole within a short period of time. The borehole was completely blocked, resulting in a rapid decline in the extraction volume of coalbed methane, and the original planned extraction target could not be achieved

For coal seams with soft coal quality, drilling under pressure is easier to achieve a longer drilling depth than normal pressure drilling, and it also has a certain inhibitory effect on hole collapse in the drilling, but it still cannot be eliminated in long-term drainage In the case of collapsed holes blocking the drilled holes, the long-term safety and smoothness of the drilled gas production channels cannot be guaranteed

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