The role of spatial variability in coal seam parameters on gas outburst behaviour during coal mining
The role of spatial variability in coal seam parameters on gas outburst behaviour during coal mining
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DOI：
10.1016/j.coal.2008.01.006
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发表时间：
2008-06-13
影响因子：
5.6
通讯作者：
Choi, S. K.
中科院分区：
文献类型：
--
作者：
Wold, M. B.;Connell, L. D.;Choi, S. K.
瓦斯突出被认为是瓦斯煤层开采过程中需要控制的潜在致命危险。澳大利亚煤矿的瓦斯突出与煤炭和周围岩石中地质结构的存在有关，其空间尺度范围从毫米到米不等。影响机制受到煤气藏变量的影响，包括气体成分、流体压力、解吸压力和速率、孔隙度、固有渗透率和相对渗透率。它们还受到地质力学变量的影响，例如强度、地应力和采矿引起的应力。这里描述的工作涉及渗透率和强度的变化对突出行为的影响。对正在运营的地下煤矿现场的关键煤炭特性进行了表征，然后将其用于一系列突出引发的假设模拟。在现场，在煤层中取芯了一系列水平孔。在孔中进行了渗透率和应力的井测试，并在实验室中测试了回收岩心的渗透率、强度和吸附特性。对于渗透率和强度，假设测量值在空间上不相关，则获得足够数量的测量值来统计地描述这些特性。对现场和实验室渗透率数据的累积概率分布的分析显示出无法线性放大的强烈尺寸效应。使用蒙特卡罗技术，这些统计描述用于生成模拟分析中使用的模型网格中的属性值的实现。随机模型方法表明，渗透率和强度场的变化可能会导致相同测量输入数据的突出和非突出结果，具体取决于工作面渗透率和强度的相应空间分布。这些结果表明该方法作为爆发风险分析和评估工具的潜在应用。 (C) 2008 Elsevier B.V. 保留所有权利。
Gas outburst is recognized as a potentially fatal hazard to be managed during the mining of gassy coal seams. Gas outbursts in Australian coal mines have been associated with the presence of geological structures in the coal and surrounding rocks, having a range of spatial scales from millimetres to metres. The contributing mechanisms are influenced by coal gas reservoir variables including gas composition, fluid pressure, desorption pressure and rate, porosity, intrinsic permeability and relative permeability. They are also influenced by geomechanical variables such as strength, in situ stress and mining-induced stress.The work described here concerns the influence of variability of permeability and strength on outburst behaviour. Key coal properties are characterised for a field site in an operational underground coal mine and then used in a series of hypothetical simulations of outburst initiation.At the field site an array of horizontal holes was cored in-seam. Well tests for permeability and stress were performed in the holes and recovered core was tested in the laboratory for permeability, strength and sorption properties. For permeability and strength sufficient numbers of measurements were obtained to describe these properties statistically assuming that the measurements are uncorrelated spatially. Analysis of the cumulative probability distributions of the field and laboratory permeability data shows a strong size effect that cannot be linearly up-scaled.Using Monte Carlo techniques, these statistical descriptions are used to generate realisations of property values across the model grid used in the simulation analyses. The stochastic model approach demonstrates that the variability of the permeability and strength fields can lead to both outburst and non-outburst outcomes from the same measured input data, depending on the corresponding spatial distribution of permeability and strength at the face. These results suggest the potential application of this approach as a tool for outburst risk analysis and assessment. (C) 2008 Elsevier B.V. All rights reserved.