Next Article in Journal
Implementation of Rapid Prototyping Tools for Power Loss and Cost Minimization of DC-DC Converters
Next Article in Special Issue
Numerical Simulation of the Propagation of Hydraulic and Natural Fracture Using Dijkstra’s Algorithm
Previous Article in Journal
A Review of Wave-to-Wire Models for Wave Energy Converters
Article Menu
Issue 7 (July) cover image

Export Article

Open AccessArticle
Energies 2016, 9(7), 514; doi:10.3390/en9070514

Experimental Study of Crack Initiation and Extension Induced by Hydraulic Fracturing in a Tree-Type Borehole Array

1
State Key Laboratory of Coal Mine Disaster Dynamics and Control, Chongqing University, Chongqing 400044, China
2
National and Local Joint Engineering Laboratory of Gas Drainage in Complex Coal Seams, Chongqing University, Chongqing 400044, China
*
Author to whom correspondence should be addressed.
Academic Editor: Enrico Sciubba
Received: 8 February 2016 / Revised: 4 May 2016 / Accepted: 4 May 2016 / Published: 30 June 2016
View Full-Text   |   Download PDF [12238 KB, uploaded 30 June 2016]   |  

Abstract

High-pressure hydraulic fracturing technology in coal and coal bed methane mines can lead to roof and floor damage, and fracture initiation disorder that leads to a “blank area”, and other issues. A new method of hydraulic fracturing is proposed to increase the homogeneous permeability of coal in underground coalmines. Numerical and other simulation tests for different forms of a tree-type, branched borehole model are presented. The results show that the branched array causes cracks to initiate from the bottom of the array, and these extend along the direction of the adjacent boreholes. Generally, as the number of branched boreholes increases, the coal seam fracture network also increase, improving the distribution of the fracture network, making the fracturing effect better. The branched boreholes appear to reduce initiation pressure and, with increasing branches, the initiation pressure decreases. A model with four tree-type, branched boreholes leads to a reduction in initiation pressure of 69%. In terms of permeability improvement technology in underground coalmines, a branched hydraulic fracturing borehole array has the advantages of reducing initiation pressure, controlling crack initiation and extension, enhancing the fracturing effect and reducing the destruction of the roof and floor. View Full-Text
Keywords: hydraulic fracturing; coal permeability; tree-type borehole array; coal bed methane; acoustic emission hydraulic fracturing; coal permeability; tree-type borehole array; coal bed methane; acoustic emission
Figures

Figure 1

This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. (CC BY 4.0).

Scifeed alert for new publications

Never miss any articles matching your research from any publisher
  • Get alerts for new papers matching your research
  • Find out the new papers from selected authors
  • Updated daily for 49'000+ journals and 6000+ publishers
  • Define your Scifeed now

SciFeed Share & Cite This Article

MDPI and ACS Style

Lu, Y.; Zuo, S.; Ge, Z.; Xiao, S.; Cheng, Y. Experimental Study of Crack Initiation and Extension Induced by Hydraulic Fracturing in a Tree-Type Borehole Array. Energies 2016, 9, 514.

Show more citation formats Show less citations formats

Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Related Articles

Article Metrics

Article Access Statistics

1

Comments

[Return to top]
Energies EISSN 1996-1073 Published by MDPI AG, Basel, Switzerland RSS E-Mail Table of Contents Alert
Back to Top