ABSTRACT
As coal mining gradually extends deeper, coal seams in China generally show high stress, high gas pressure and low permeability, bringing more difficulty to coal mining. Therefore, in order to strengthen gas extraction, it is necessary to carry out reservoir reconstruction after deep coal seams reached. In this paper, the distribution and evolution laws of fracture zone overlaying strata of J15 seam in Pingdingshan No. 10 coal mine after excavation were studied by combining similar simulation and numerical simulation, meanwhile, the gas transport law within fracture zone was numerically simulated. The results show that the fracture zone reaches a maximum of 350 mm in the vertical direction and is 75 mm away from W9,10 coal seams in vertical distance. Since W9,10 coal seams are in an area greatly affected by the bending zone of J15 coal seam under the influence of mining, the mining of J15 coal seam will exert a strong permeability enhancement effect on W9,10 coal seams. The J15 coal seam can act as a long-distance protective layer of W9,10 coal seams to eliminate the outburst danger of the long-distance coal seams in bending zone with coal and gas outburst danger, thereby achiev¬ing safe, productive and efficient integrated mining of coal and gas resources. The gas flux of mining-induced fractures in the trapezoidal stage of mining-induced fracture field is far greater than that in the overlaying stratum matrix. The horizontal separation fractures and vertical broken fractures within the mining-induced fracture field act as passages for gas-flow. Compared with gas transport in the overlaying stratum matrix, the horizontal separation fractures and vertical broken fractures within the mining-induced fracture field play a role in guiding gas-flow. The research results can provide theoretical support for the arrangement of high-level gas extraction boreholes in roof fracture zones.
KEYWORDS
PAPER SUBMITTED: 2018-05-26
PAPER REVISED: 2018-06-21
PAPER ACCEPTED: 2018-11-15
PUBLISHED ONLINE: 2019-04-14
THERMAL SCIENCE YEAR
2019, VOLUME
23, ISSUE
Supplement 3, PAGES [S907 - S915]
- Liu T., et al., An Integrated Technology for Gas Control and Green Mining in Deep Mines Based on Ultra-Thin Seam Mining, Environmental Earth Sciences, 76(2017), 6, pp.243
- Xie H.B., et al., Research and Consideration of Deep Coal Mining and Critical Mining Depth, Journal of China Coal Society, 37(2012),37, pp.535-542
- Liu X.F., et al., Effects of Gas Pressure on Bursting Liability of Coal Under Uniaxial Conditions, Journal of Natural Gas Science and Engineering, 39(2017), Jan., pp. 90-100
- Liu T., et al., Influence of Coupled Effect Among Flaw Parameters on Strength Characteristic of Precracked Specimen: Application of Response Surface Methodology and Fractal Method, Journal of Natural Gas Science and Engineering, 26(2015), 9, pp. 857-866
- Liu T., et al., Investigation on Mechanical Properties and Damage Evolution of Coal After Hydraulic Slotting, Journal of Natural Gas Science and Engineering, 24(2015), Apr., pp. 489-499
- Yuan L., The Theory of Pressure Relieved Gas Extraction and Technique System of Integrated Coal Production and Gas Extraction, Journal of China Coal Society, 01(2009), Jan., pp. 1-8
- Yuan L., Xue S., Defining Outburst-Free Zones in Protective Mining With Seam Gas Content-Method and Application, Journal of China Coal Society, 39(2014), 09, pp. 1786-1791
- Li W., Study on Mechanical Characteristics of Coal and Rock and Gas Migration Law Under the Influence of Mining, Chongqing University, 2014
- Qian M.G., Xu J.L., Study on the "O-Shape" Circle Distribution Characteristics of Mining-Induced Fractures in the Overlaying Strata, Journal of China Coal Society, 05(1998), pp. 20-23
- Xu J.L., Qian M.G., Study and Application of Mining-Induced Fracture Distribution in Green Mining, Journal of China University of Mining & Technology, 02(2004), pp. 17-20
- Lin H., et al., Experimental Analysis of Dynamic Evolution Model of Mining-Induced Fissure Zone in Overlaying Strata, Journal of Mining & Safety Engineering,02(2011), pp. 298-303
- Gao, M.Z., et al., Field Experiments on Fracture Evolution and Correlations Between Connectivity and Abutment Pressure Under Top Coal Caving Conditions. International Journal of Rock Mechanics and Mining Science, 111(2018), Oct., pp. 84-93
- Zhang C., et al., Evaluating Pressure-Relief Mining Performances Based on Surface Gas Venthole Extraction Data in Longwall Coal Mines, Journal of Natural Gas Science and Engineering, 24(2015), Apr., pp. 431-440
- Wang L., et al., Fracture Evolution and Pressure Relief Gas Drainage from Distant Protected Coal Seams Under an Extremely Thick Key Stratum, Journal of China University of Mining & Technology, 18(2008), 2, pp. 182-186
- Yin G., et al., Mechanical Behavior and Permeability Evolution of Gas Infiltrated Coals during Protective Layer Mining, International Journal of Rock Mechanics and Mining Sciences, 80(2015), Aug., 292-301
- Sang S., et al., Stress Relief Coalbed Methane Drainage by Surface Vertical Wells in China, International Journal of Coal Geology, 82(2010), 3-4, pp. 196-203
- Zhang D., et al., Coal and Rock Fissure Evolution and Distribution Characteristics of Multi-Seam Mining, International Journal of Mining Science and Technology, 23(2013), 6, pp. 835-840
- Yin W., et al., Mechanical Analysis of Effective Pressure Relief Protection Range of Upper Protective Seam Mining, International Journal of Mining Science and Technology, 27(2017), 3, pp. 537-543
- Yang W., et al., Stress Evolution with Time and Space During Mining of a Coal Seam, International Journal of Rock Mechanics and Mining Sciences, 48(2011), 7, pp. 1145-1152
- Liu T., Lin B.Q., Yang W., Impact of Matrix-Fracture Interactions on Coal Permeability: Model Development and Analysis, Fuel, 207(2017), Jun., pp. 522-532