Hole-digging and temperature-reducing drilling tool for outburst coal seam and drilling method thereof

Abstract

The present invention is cooled drilling tool and drilling process for protuberant coal bed. The drilling tool includes one cooled drill stem with surface spiral conveying slot for penetrating the drilled hole and carrying out friction heat from the drill stem, and one antijamming drill bit assembly connected to the cooled drill stem and comprising one drill bit and one non-return valve member to prevent the drill stem hole from blocking with coal slag. The drilling process includes the following steps: providing the drill stem with high pressure air source and starting the drilling machine to drill, and lowering the rotation speed and stopping propelling while the drilling machine rotates after partial jamming of the drill stem to lower the temperature of the drill tool and penetrate the drilled hole. The present invention can improve the effect of drilling in protuberant coal bed.

Description

technical field [0001] The invention relates to a drilling tool used for drilling outburst coal seams in coal mines and a drilling method using the drilling tool. Background technique [0002] In the field of coal mine industry, before mining the outburst coal seam, it is necessary to drill holes in the outburst coal seam to drain the gas in the coal seam. [0003] At present, tunnel hydraulic drilling rigs are generally used in domestic outburst coal seam drainage drilling. The drill pipe is made of smooth steel pipe. Drill bit, high-pressure air blows the drilling slag out of the drill hole. However, in the process of drilling outburst coal seams using the above methods, phenomena such as hole collapse, coal guns, and borehole blockage often occur. Phenomena such as heat generation (drilling and combustion accidents have occurred many times in China), therefore, it is very difficult to drill deep holes in protruding coal seams. [0004] In order to solve the problem of ...

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Problems solved by technology

However, in the process of drilling outburst coal seams using the above methods, phenomena such as hole collapse, coal guns, and borehole blockage often occur. Phenomena such as heat generation (drilling and burning accidents have occurred many times in China), therefore, it is very difficult to drill deep holes in protruding coal seams

[0004] In order to solve the problem of difficult drilling of deep holes in outburst coal seams, the applicant described a "equipment and method for pressure-holding drilling and cutting in outburst coal seams" in another patent application with application number 200510059889.1, but the construction process is complicated , high construction cost

[0005] In addition, Patent No. 01267191.6 also describes a "drill pipe for deep-hole drilling rig with high gas in soft coal seams", but the use of this kind of drill pipe is greatly restricted due to the difficulty in matching the strength of the drill pipe and the connecting thread; Similarly, the No. 02800916.9 patent application (patent number) describes a "stepped tubular drill pipe and drilling rig". However, due to the huge size of the equipment, it is limited in space when used in the well, and the recovery of the cut tubular drill pipe is difficult.

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