Influence of Water Injection Fracturing on Crack Damage in Soft Coal and Application in Gas Extraction

Zhirong Wang^1*, Jianshi Jin¹, Zhongyang Hang¹, Xiangzhi Hu²

¹School of Environment and Water Conservancy Engineering, Zhengzhou University, Zhengzhou, China.
²Gas Well Engineering Research Center of Henan, Zhengzhou, China.

DOI: 10.4236/jpee.2014.24001                

Abstract

In order to study the hypotonic and rheological particularity of “three soft” coal seam in west Henan, China, this paper explored the stress and damage characteristics of crack in coal under condition of water injection fracturing based on ABAQUS platform; The cohesive element in T-P damage evolution criterion was used to describe the approximately linear relationship between crack width and extending distance in soft coal. The simulation results show that stress evolution and crack damage in soft coal is a gradually developing process under condition of water injection fracturing. When the static pressure is 4 - 10 MPa, and the injection time is about 1 - 2 hours, the damage range of crack in soft coal can basically reach an ideal data of 80 - 100 m, and then greatly improve the hypotonic performance of “three soft” coal seam.

Keywords

“Three Soft” Coal Seam; Directional Water Injection Fracturing; Crack Damage; Gas Extraction

Conflicts of Interest

The authors declare no conflicts of interest.

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