ZUO W Q, LI Y Q, LIU Y W,et al.Experimental study on water and slag transportation mechanism and high-efficiency extraction in downward boreholes[J].Journal of Henan Polytechnic University(Natural Science) ,2023,42(2):19-26.

doi:10.16186/j.cnki.1673-9787.2021080064

Received:2021/08/18

Revised:2021/11/16

Published:2023/03/25

Experimental study on water and slag transportation mechanism and high-efficiency extraction in downward boreholes

ZUO Weiqin1,2, LI Yunqiang1,2, LIU Yanwei1,2, HAN Hongkai1,2, JIA Haojie1,2

1.State Key Laboratory Cultivation Base for Gas Geology and Gas Control，Henan Polytechnic University，Jiaozuo  454000，Henan，China；2.School of Safety Science and Engineering，Henan Polytechnic University，Jiaozuo  454000，Henan，China

Abstract:In order to solve the problems of water and slag accumulation and poor effect of gas drainage in downward boreholes，based on step-by-step transportation mode of“water injection slag，pressure air drainage”way，a transportation mechanism of high-efficient circulating water and slag drainage in downhole drilling was put forward.An integrative equipment of downhole drainage and slag extraction was developed，and field tests were carried out in Yian Coal Mine.The results showed that the cuttings with size 8 mm or less could be discharged effectively.The drainage operation could be completed in 10 min without external water supply.After the drainage and slag discharge operation，the concentration of single boreholes was increased from 0 to 60%~85%.When there was additional water source in the borehole，the time of high efficient extraction could be prolonged by using irregular drainage and slag discharge.A long examination of the effects showed that the gas drainage concentration was increased by 2.8~12.6 times.Studies have shown that，the equipment could effectively discharge the water slag accumulated at the bottom of the borehole and the fissure water flowing into the borehole in the process of extraction，and could realize the rapid switching and circulation operation of three working states of slag discharge，water discharge and gas drainage，improve the pumping efficiency of the downhole drilling.This provided technical guarantee for hydraulic anti-permeability technology of down-hole and high-efficiency gas extraction.

Key words:gas drainage;downward borehole;water and slag transportation;effect of gas drainage

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