韩城矿区煤层结构特征及其对微粒生成的影响

煤层气开发利用具有“资源、安全、环保”多重经济效益和社会效益。韩城矿区是我国煤层气勘探开发试验先导区之一,区内煤层气井中煤粉等固相微粒产出现象较为突出。为了查明韩城矿区煤层结构特征及其对微粒生成的影响作用,分析了煤层气开发主力煤层的煤层结构复杂程度,讨论了3、5和11号煤层中夹矸发育规律,表征了物理模拟实验条件下煤中夹矸与微粒生成的关系。结果表明:按主力煤层由早至晚发育顺序,其煤层结构由复杂趋于简单、夹矸发育层数减小、夹矸总厚降低。3号煤层中夹矸主要发育在桑树坪、下峪口及王峰井田。5号煤层中夹矸发育在矿区南部,夹矸总厚高值区集中在象山、薛峰和龙亭一带。11号煤层中夹矸分布遍及全区,具东部边缘发育程度高、西部发育程度低的特征。在物理破坏、水岩反应和层间压差作用下,煤中夹矸会成为微粒生成层位。泥质夹矸对微粒的生成数量、运移距离及相应的储层渗透性伤害影响尤甚。加强煤层结构特征分析有助于查明煤中夹矸岩性变化及分布特征,进而为有效防治微粒生成提供保障。

Coal Seam Texture Features and Their Influence on Particles Generation in Hancheng Mining Area

The exploitation and utilization of CBM have resource,security and environment protection etc multiple economic and social benefits.The Hancheng mining area is one of experimental pilot areas of CBM exploitation and utilization in China.The phenomenon of solid particles in CBM wells in the area is rather prominent.To identify coal seam texture features and their influence on particle generation in the area has analyzed complexity of main coal seams in CBM exploitation.The paper has also discussed coal partings development pattern in coal Nos.3,5 and 11,characterized the relation between coal parting and particles generation.The result has shown that according to main coal seams development sequence from early to late,coal seam texture will tend from complex toward simple;parting number cut down,and total thickness decrease.Partings in coal No.3 are mainly developed in the Sangshuping,Xiayukou and Wangfeng minefields;in coal No.5 mainly developed in the southern part of mining area;while the total thickness high areas mainly concentrated in the Xiangshan,Xuefeng and Longting surroundings;in coal No.11 distributed all over the mining area and presented features of highly developed at eastern margin and lowering down in western part.Under physical destruction,water-rock reaction and interlayer pressure differentials,coal parting will become generation horizon of particles.Impact from argillaceous parting is particularly high on particle generated amount,migration distance and corresponding permeability harm.To strengthen coal seam texture features analysis might aid identification of coal parting lithologic variation and distribution features,and then provides guarantee for particles generation control effectively.