Numerical Modeling on Hydraulic Fracturing in Coal-Rock Mass for Enhancing Gas Drainage

The mechanism of how hydraulic fracturing influences gas drainage in coal-rock mass is still not clear due to its complex mechanism. In this work, statistical distributions are firstly introduced to describe heterogeneity of coal-rock mass; a novel simultaneously coupled mathematical model, which ca...

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Main Authors: Zhigang Yuan, Yaohua Shao
Format: Article
Language:English
Published: Wiley 2018-01-01
Series:Advances in Civil Engineering
Online Access:http://dx.doi.org/10.1155/2018/1485672
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author Zhigang Yuan
Yaohua Shao
author_facet Zhigang Yuan
Yaohua Shao
author_sort Zhigang Yuan
collection DOAJ
description The mechanism of how hydraulic fracturing influences gas drainage in coal-rock mass is still not clear due to its complex mechanism. In this work, statistical distributions are firstly introduced to describe heterogeneity of coal-rock mass; a novel simultaneously coupled mathematical model, which can describe the fully coupled process including seepage-damage coupling during hydraulic fracturing process and subsequent gas flow during gas drainage process, is established; its numerical implementation procedure is coded into a Matlab program to calculate the damage variables, and it partly uses COMSOL solver to obtain numerical solutions of governing equations with damage-flow coupling; the mathematical model and its implementation are validated for initial damage pressure and mode of a single solid model without considering flow-damage coupling, as well as fracture initiation pressure and influence of heterogeneity on damage evolution of hydraulic fracturing considering flow-damage coupling; and finally, based on an engineering practice of hydraulic fracturing with two boreholes, the mechanism of how hydraulic fracturing influences gas drainage is investigated, numerical simulation results indicate that coal-rock mass pore-fissure structure has been improved, and there would exist a gas migration channel with characteristics of higher porosity and lower stresses, which demonstrates significant effects and mechanism of hydraulic fracturing on improving coal-rock permeability and enhancing gas drainage. The research results provide a guide for operation of hydraulic fracturing and optimal layout of gas drainage boreholes.
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spelling doaj-art-c5183abacd804becb9e34489e7e82e6e2025-08-20T03:22:42ZengWileyAdvances in Civil Engineering1687-80861687-80942018-01-01201810.1155/2018/14856721485672Numerical Modeling on Hydraulic Fracturing in Coal-Rock Mass for Enhancing Gas DrainageZhigang Yuan0Yaohua Shao1School of Resources, Environment and Safety Engineering, Hunan University of Science and Technology, Xiangtan, Hunan 411201, ChinaSchool of Resources, Environment and Safety Engineering, Hunan University of Science and Technology, Xiangtan, Hunan 411201, ChinaThe mechanism of how hydraulic fracturing influences gas drainage in coal-rock mass is still not clear due to its complex mechanism. In this work, statistical distributions are firstly introduced to describe heterogeneity of coal-rock mass; a novel simultaneously coupled mathematical model, which can describe the fully coupled process including seepage-damage coupling during hydraulic fracturing process and subsequent gas flow during gas drainage process, is established; its numerical implementation procedure is coded into a Matlab program to calculate the damage variables, and it partly uses COMSOL solver to obtain numerical solutions of governing equations with damage-flow coupling; the mathematical model and its implementation are validated for initial damage pressure and mode of a single solid model without considering flow-damage coupling, as well as fracture initiation pressure and influence of heterogeneity on damage evolution of hydraulic fracturing considering flow-damage coupling; and finally, based on an engineering practice of hydraulic fracturing with two boreholes, the mechanism of how hydraulic fracturing influences gas drainage is investigated, numerical simulation results indicate that coal-rock mass pore-fissure structure has been improved, and there would exist a gas migration channel with characteristics of higher porosity and lower stresses, which demonstrates significant effects and mechanism of hydraulic fracturing on improving coal-rock permeability and enhancing gas drainage. The research results provide a guide for operation of hydraulic fracturing and optimal layout of gas drainage boreholes.http://dx.doi.org/10.1155/2018/1485672
spellingShingle Zhigang Yuan
Yaohua Shao
Numerical Modeling on Hydraulic Fracturing in Coal-Rock Mass for Enhancing Gas Drainage
Advances in Civil Engineering
title Numerical Modeling on Hydraulic Fracturing in Coal-Rock Mass for Enhancing Gas Drainage
title_full Numerical Modeling on Hydraulic Fracturing in Coal-Rock Mass for Enhancing Gas Drainage
title_fullStr Numerical Modeling on Hydraulic Fracturing in Coal-Rock Mass for Enhancing Gas Drainage
title_full_unstemmed Numerical Modeling on Hydraulic Fracturing in Coal-Rock Mass for Enhancing Gas Drainage
title_short Numerical Modeling on Hydraulic Fracturing in Coal-Rock Mass for Enhancing Gas Drainage
title_sort numerical modeling on hydraulic fracturing in coal rock mass for enhancing gas drainage
url http://dx.doi.org/10.1155/2018/1485672
work_keys_str_mv AT zhigangyuan numericalmodelingonhydraulicfracturingincoalrockmassforenhancinggasdrainage
AT yaohuashao numericalmodelingonhydraulicfracturingincoalrockmassforenhancinggasdrainage