Coal Engineering ›› 2025, Vol. 57 ›› Issue (2): 75-81.doi: 10. 11799/ ce202502011

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A new “two-plug-one-grout” sealing technology for long distance upward cross-layer drilling

  

  • Received:2024-04-03 Revised:2024-07-01 Online:2025-02-10 Published:2025-04-28

Abstract:

In order to solve the problem that the sealing material for long-distance layer drilling upwards will squeeze out the front end plug of the drilling due to its own gravity and it is difficult to penetrate the upper side of the long-distance layer drilling upwards. Adopting a new "two plugs and one injection" sealing process to solve the problem. Through simulation experiments using 80mm diameter steel pipes to simulate drilling, it was found that the material of the sealing section filled the entire sealing space, and the slurry at the front end of the bag was tight. The on-site experimental study on the gas drainage roadway of the 20 # coal seam floor in the 12 concentration roadway of Zhongheng Coal Mine in Guizhou Province shows that the new "two plugs and one injection" sealing technology is less affected by changes in drilling angle, and its average gas drainage concentration is always above 60%. However, the average gas drainage concentration of the "two plugs and one injection" sealing technology always decreases with the increase of drilling angle, and its maximum average gas drainage concentration is only 36.3%; The average gas drainage concentration attenuation rate of the new "two plugs and one injection" sealing process is less than 0.02, while the average gas drainage concentration attenuation rate of the "two plugs and one injection" sealing process is greater than 0.2. The results indicate that the new"two plugs and one injection" sealing process is more suitable for upward long-distance drilling through layers than the "two plugs and one injection" sealing process.

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