Experimental Study of Crack Initiation and Extension Induced by Hydraulic Fracturing in a Tree-Type Borehole Array
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 un...
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| Format: | Article |
| Language: | English |
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MDPI AG
2016-06-01
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| Series: | Energies |
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| Online Access: | http://www.mdpi.com/1996-1073/9/7/514 |
| _version_ | 1828112890562871296 |
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| author | Yiyu Lu Shaojie Zuo Zhaolong Ge Songqiang Xiao Yugang Cheng |
| author_facet | Yiyu Lu Shaojie Zuo Zhaolong Ge Songqiang Xiao Yugang Cheng |
| author_sort | Yiyu Lu |
| collection | DOAJ |
| description | 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. |
| first_indexed | 2024-04-11T11:57:21Z |
| format | Article |
| id | doaj.art-561853543851411791899802add07915 |
| institution | Directory Open Access Journal |
| issn | 1996-1073 |
| language | English |
| last_indexed | 2024-04-11T11:57:21Z |
| publishDate | 2016-06-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Energies |
| spelling | doaj.art-561853543851411791899802add079152022-12-22T04:25:06ZengMDPI AGEnergies1996-10732016-06-019751410.3390/en9070514en9070514Experimental Study of Crack Initiation and Extension Induced by Hydraulic Fracturing in a Tree-Type Borehole ArrayYiyu Lu0Shaojie Zuo1Zhaolong Ge2Songqiang Xiao3Yugang Cheng4State Key Laboratory of Coal Mine Disaster Dynamics and Control, Chongqing University, Chongqing 400044, ChinaState Key Laboratory of Coal Mine Disaster Dynamics and Control, Chongqing University, Chongqing 400044, ChinaState Key Laboratory of Coal Mine Disaster Dynamics and Control, Chongqing University, Chongqing 400044, ChinaState Key Laboratory of Coal Mine Disaster Dynamics and Control, Chongqing University, Chongqing 400044, ChinaState Key Laboratory of Coal Mine Disaster Dynamics and Control, Chongqing University, Chongqing 400044, ChinaHigh-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.http://www.mdpi.com/1996-1073/9/7/514hydraulic fracturingcoal permeabilitytree-type borehole arraycoal bed methaneacoustic emission |
| spellingShingle | Yiyu Lu Shaojie Zuo Zhaolong Ge Songqiang Xiao Yugang Cheng Experimental Study of Crack Initiation and Extension Induced by Hydraulic Fracturing in a Tree-Type Borehole Array Energies hydraulic fracturing coal permeability tree-type borehole array coal bed methane acoustic emission |
| title | Experimental Study of Crack Initiation and Extension Induced by Hydraulic Fracturing in a Tree-Type Borehole Array |
| title_full | Experimental Study of Crack Initiation and Extension Induced by Hydraulic Fracturing in a Tree-Type Borehole Array |
| title_fullStr | Experimental Study of Crack Initiation and Extension Induced by Hydraulic Fracturing in a Tree-Type Borehole Array |
| title_full_unstemmed | Experimental Study of Crack Initiation and Extension Induced by Hydraulic Fracturing in a Tree-Type Borehole Array |
| title_short | Experimental Study of Crack Initiation and Extension Induced by Hydraulic Fracturing in a Tree-Type Borehole Array |
| title_sort | experimental study of crack initiation and extension induced by hydraulic fracturing in a tree type borehole array |
| topic | hydraulic fracturing coal permeability tree-type borehole array coal bed methane acoustic emission |
| url | http://www.mdpi.com/1996-1073/9/7/514 |
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