Coal Engineering ›› 2021, Vol. 53 ›› Issue (2): 85-89.doi: 10.11799/ce202102017

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Study on the application of hydraulic anti-reflection measures in gas extraction of broken soft coal seam in Xinjiang

  

  • Received:2020-03-11 Revised:2020-05-21 Online:2021-02-20 Published:2021-05-10

Abstract: In order to solve the problems of poor gas permeability and difficult gas drainage in broken and outburst coal seams in Xinjiang, a variety of hydraulic measures to increase permeability are applied to the gas extraction of broken soft outburst coal seam. High pressure hydraulic cutting and hydraulic fracturing tests were carried out in No. 4 coal seam of Aiweiergou mining area in Xinjiang, and comparative analysis was made from the aspects of extraction concentration, pure flow, attenuation, construction period and construction process. The research shows that the extraction concentration and the pure flow rate after hydraulic cutting and hydraulic fracturing show a pattern of increasing first, then attenuating, and finally stable. The average single hole concentration of the hydraulic cutting extraction hole and the hydraulic fracturing extraction hole was increased by 7.7 and 5.7 times compared with the ordinary dense extraction hole, respectively, and the average pure flow rate of the single hole was increased by 3.4 and 2.1 times, respectively. After the return period, the drainage pure flow rate decayed exponentially, and the former decayed significantly faster than the latter. After the adoption of hydraulic measures, the amount of drilling work has been greatly reduced, and the total construction period has been significantly reduced.