Coal mine methane (CMM) accumulation and permeability distribution characterization are the bases for a successful CMM drainage design. Before extending degassing activities, the prediction of the gas pressure and permeability distributions of the pre-drainage area is recommended. The effects of CMM geology on gas occurrence and coal permeability have drawn much attention and contributed to numerous research findings. However, the loco-regional distribution characteristics of the gas occurrence and coal permeability induced by landform characteristics have barely been investigated. This paper presents a quantitative case study on the non-uniform distributions of the gas pressure and coal permeability induced by the Loess Plateau geomorphology. Based on the collection and analysis of a large amount of data, the non-uniform distribution of the burial depth was first obtained. The relationship between the burial depth and gas pressure was analyzed by using the safety line method. A series of efforts were made to perform experimental tests for determining the competing influences of the effective stresses and sorption-induced strain on the coal permeability, and the relationship between the burial depth and coal permeability was analyzed by using the modified PM model. Finally, a quantitative evaluation of the non-uniform distributions of the gas pressure and coal permeability induced by the Loess Plateau geomorphology was achieved. The results showed that the statistical burial depth, gas pressure, and permeability of the No. 3 coal seam were irregular with large loco-regional changes, and the range of the burial depth was from 349 to 479 m. Further, the predicted pressure was from 0.81 to 1.66 MPa, and the predicted permeability was from 0.0155 to 0.01968 mD. When using both the gas pressure and coal permeability as the evaluation indices of the difficulty of gas drainage, the study area could be divided into six parts and classified into two groups. The division of a coal seam influenced by the Loess Plateau geomorphology will provide essential information formulation and economical plan to degas it.

中文翻译：

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黄土高原地貌引起的煤层气储层气压与煤渗透率的非均匀分布：以鄂尔多斯盆地为例

煤矿瓦斯（CMM）的积累和渗透率分布特征是成功进行CMM排水设计的基础。建议在扩展除气活动之前，对预排水区的气压和渗透率分布进行预测。CMM地质学对瓦斯发生和煤渗透率的影响引起了广泛关注，并为众多研究成果做出了贡献。但是，很少研究瓦斯发生的局部区域分布特征和地形特征引起的煤渗透性。本文对黄土高原地貌引起的气压和煤渗透率的非均匀分布进行了定量的案例研究。基于大量数据的收集和分析，首先获得了埋藏深度的不均匀分布。采用安全线法分析了埋藏深度与气压的关系。为了确定有效应力和吸附引起的应变对煤渗透率的竞争影响，进行了一系列试验，并使用改进的PM模型分析了埋深与煤渗透率之间的关系。最后，对黄土高原地貌引起的气压和煤渗透率的非均匀分布进行了定量评价。结果表明，三号煤层的统计埋深，瓦斯压力和渗透率是不规则的，局部区域变化较大，埋深范围为349〜479m。进一步，预测压力为0.81至1.66 MPa，预测渗透率为0.0155至0.01968 mD。将瓦斯压力和煤层渗透率作为瓦斯抽放难度的评价指标时，研究区可分为六个部分，分为两组。受黄土高原地貌影响的煤层划分将为脱气提供必要的信息制定和经济计划。