Variation law of roof stress and permeability enhancement effect of repeated hydraulic fracturing in low‐permeability coal seam

Abstract Hydraulic fracturing experiments were conducted to study the change of initial fracture pressure and roof stress under repeated hydraulic fracturing in coal mines and to investigate the actual penetration enhancement effect on coal seams. The results show that as the fracturing is repeated,...

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Main Authors: Li Liangwei, Wu Wenbin
Format: Article
Language:English
Published: Wiley 2021-09-01
Series:Energy Science & Engineering
Subjects:
Online Access:https://doi.org/10.1002/ese3.909
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author Li Liangwei
Wu Wenbin
author_facet Li Liangwei
Wu Wenbin
author_sort Li Liangwei
collection DOAJ
description Abstract Hydraulic fracturing experiments were conducted to study the change of initial fracture pressure and roof stress under repeated hydraulic fracturing in coal mines and to investigate the actual penetration enhancement effect on coal seams. The results show that as the fracturing is repeated, a lower initiation pressure is required. The roof stress changes consistently with water injection pressure. First, the stress in the area around the water injection hole gradually increases, and then stress transfers to the surroundings. With the re‐implementation of fracturing, the area of increased stress expands, and the scope of influence of hydraulic fracturing also becomes larger. When fracturing in a coal mine, for the same total fracturing time, the total water injection volume of repeated fracturing is 35% higher than that of single fracturing, and the affected area is increased by 31%. The concentration of repeated hydraulic fracturing is about 36% higher than that of a single hydraulic fracturing, and the pure flow of gas drainage is increased by about 1.3 times. The results of this study can guide the efficient implementation of hydraulic fracturing underground in coal mines, so as to achieve a larger impact range of coal seam hydraulic fracturing and better gas drainage effects.
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spelling doaj.art-f44cce451f644a49b8e04d9d0534e5572022-12-21T21:28:18ZengWileyEnergy Science & Engineering2050-05052021-09-01991501151610.1002/ese3.909Variation law of roof stress and permeability enhancement effect of repeated hydraulic fracturing in low‐permeability coal seamLi Liangwei0Wu Wenbin1China Coal Technology and Engineering Group Chongqing Research Institute Chongqing ChinaChina Coal Technology and Engineering Group Chongqing Research Institute Chongqing ChinaAbstract Hydraulic fracturing experiments were conducted to study the change of initial fracture pressure and roof stress under repeated hydraulic fracturing in coal mines and to investigate the actual penetration enhancement effect on coal seams. The results show that as the fracturing is repeated, a lower initiation pressure is required. The roof stress changes consistently with water injection pressure. First, the stress in the area around the water injection hole gradually increases, and then stress transfers to the surroundings. With the re‐implementation of fracturing, the area of increased stress expands, and the scope of influence of hydraulic fracturing also becomes larger. When fracturing in a coal mine, for the same total fracturing time, the total water injection volume of repeated fracturing is 35% higher than that of single fracturing, and the affected area is increased by 31%. The concentration of repeated hydraulic fracturing is about 36% higher than that of a single hydraulic fracturing, and the pure flow of gas drainage is increased by about 1.3 times. The results of this study can guide the efficient implementation of hydraulic fracturing underground in coal mines, so as to achieve a larger impact range of coal seam hydraulic fracturing and better gas drainage effects.https://doi.org/10.1002/ese3.909gas drainagelow‐permeability coal seamrepeated hydraulic fracturingsimulation experiment
spellingShingle Li Liangwei
Wu Wenbin
Variation law of roof stress and permeability enhancement effect of repeated hydraulic fracturing in low‐permeability coal seam
Energy Science & Engineering
gas drainage
low‐permeability coal seam
repeated hydraulic fracturing
simulation experiment
title Variation law of roof stress and permeability enhancement effect of repeated hydraulic fracturing in low‐permeability coal seam
title_full Variation law of roof stress and permeability enhancement effect of repeated hydraulic fracturing in low‐permeability coal seam
title_fullStr Variation law of roof stress and permeability enhancement effect of repeated hydraulic fracturing in low‐permeability coal seam
title_full_unstemmed Variation law of roof stress and permeability enhancement effect of repeated hydraulic fracturing in low‐permeability coal seam
title_short Variation law of roof stress and permeability enhancement effect of repeated hydraulic fracturing in low‐permeability coal seam
title_sort variation law of roof stress and permeability enhancement effect of repeated hydraulic fracturing in low permeability coal seam
topic gas drainage
low‐permeability coal seam
repeated hydraulic fracturing
simulation experiment
url https://doi.org/10.1002/ese3.909
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AT wuwenbin variationlawofroofstressandpermeabilityenhancementeffectofrepeatedhydraulicfracturinginlowpermeabilitycoalseam