Geostatistical modeling of the gas emission zone and its in-place gas content for Pittsburgh-seam mines using sequential Gaussian simulation
Geostatistical modeling of the gas emission zone and its in-place gas content for Pittsburgh-seam mines using sequential Gaussian simulation
复制标题
DOI：
10.1016/j.coal.2011.10.010
复制
发表时间：
2012-02-01
影响因子：
5.6
通讯作者：
Goodman, Gerrit
中科院分区：
文献类型：
--
作者：
Karacan, C. Oezgen;Olea, Ricardo A.;Goodman, Gerrit
确定瓦斯涌出区的大小、瓦斯源的位置以及特别是这些区域中保留的瓦斯量是在长壁采煤中设计成功的瓦斯控制策略和有效的通风系统的最重要的步骤之一。瓦斯涌出区的形成和可能可用于迁移到矿井中的潜在天然气储量（GIP）是当地地质和岩石性质的因素，通常表现出连续性的空间变化，也可能表现出几何各向异性。地质统计学方法在这里用于建模和预测的气体量，并评估其相关的不确定性，在瓦斯排放区的长壁矿井甲烷control.This研究使用的核心数据从276垂直勘探钻孔钻从表面到底部的匹兹堡煤层在矿区的北方阿巴拉契亚盆地。在确定瓦斯涌出区的重要煤层和非煤层后，对不同地层的数据进行单变量统计和半方差分析，以确定各种属性的分布和连续性。顺序模拟进行随机评估这些属性，如气体含量，地层厚度，地层位移。在此基础上，对该矿区匹兹堡煤层冒落带和裂隙带的瓦斯地质储量及其不确定性进行了计算。网格消隐用于从整个建模区域中隔离实际面板上的体积，并计算与长壁矿井排放直接相关的气体量。结果表明，在匹兹堡煤层，在塌陷区和断裂区，以及位移的主要岩石单元，天然气的地方，表现出空间相关性，可以使用地质统计学方法建模和估计。这项研究表明，GIP体积可能会改变高达3 MMscf每英亩，在一个多面板区，可能会在气体排放区的甲烷总量为9亿立方英尺。因此，应相应地设计通风和气体捕获系统。此外，瓦斯涌出带内的岩石位移在空间上是分布的。从工程和实际的角度来看，GIP的空间分布和岩石位移的分布应与矿井排放和采空区瓦斯排放量相关。由Elsevier出版。
Determination of the size of the gas emission zone, the locations of gas sources within, and especially the amount of gas retained in those zones is one of the most important steps for designing a successful methane control strategy and an efficient ventilation system in longwall coal mining. The formation of the gas emission zone and the potential amount of gas-in-place (GIP) that might be available for migration into a mine are factors of local geology and rock properties that usually show spatial variability in continuity and may also show geometric anisotropy. Geostatistical methods are used here for modeling and prediction of gas amounts and for assessing their associated uncertainty in gas emission zones of longwall mines for methane control.This study used core data obtained from 276 vertical exploration boreholes drilled from the surface to the bottom of the Pittsburgh coal seam in a mining district in the Northern Appalachian basin. After identifying important coal and non-coal layers for the gas emission zone, univariate statistical and semivariogram analyses were conducted for data from different formations to define the distribution and continuity of various attributes. Sequential simulations performed stochastic assessment of these attributes, such as gas content, strata thickness, and strata displacement. These analyses were followed by calculations of gas-in-place and their uncertainties in the Pittsburgh seam caved zone and fractured zone of longwall mines in this mining district. Grid blanking was used to isolate the volume over the actual panels from the entire modeled district and to calculate gas amounts that were directly related to the emissions in longwall mines. Results indicated that gas-in-place in the Pittsburgh seam, in the caved zone and in the fractured zone, as well as displacements in major rock units, showed spatial correlations that could be modeled and estimated using geostatistical methods. This study showed that GIP volumes may change up to 3 MMscf per acre and, in a multi-panel district, may total 9 Bcf of methane within the gas emission zone. Therefore, ventilation and gas capture systems should be designed accordingly. In addition, rock displacements within the gas emission zone are spatially distributed. From an engineering and practical point of view, spatial distributions of GIP and distributions of rock displacements should be correlated with in-mine emissions and gob gas venthole productions. Published by Elsevier By.