保德煤矿奥灰含水层顶部地层岩性及孔隙性特征分析

华北煤田奥灰含水层顶部的隔水性能是该区煤矿实现带压开采的关键保障，而地层的岩性及孔隙性是反映其隔水性的重要指标。以神东保德煤矿奥灰含水层顶部地层为研究背景，依据现场勘探成果，采用矿物成分分析及室内压汞试验，对奥灰含水层顶部岩层的岩性及孔隙性进行了试验研究。研究结果表明，奥灰含水层顶部地层岩石矿物组分以方解石为主，吸水、渗透性较差，孔隙结构性较差，连通孔隙占总孔隙体积的5%~7%，主要孔隙为孔径025 μm的难渗流微小孔隙，孔隙特征反映出奥灰含水层顶部地层具有良好的阻隔水性。研究成果为奥灰含水层顶部地层隔水性能研究及评价提供了重要的参考依据，为该矿区乃至其他类似矿区底板奥灰水害防治及带压开采奠定了基础。

Analysis on lithology and porosity characteristics of top formation of Ordovician limestone aquifer in Baode Coal Mine

The waterproof performance of the top of Ordovician limestone aquifer in North China coalfield is the key guarantee for coal mines in this area to realize mining under pressure,and the lithology and porosity of the formation are important indicators to reflect its waterproof performance.Taking the top stratum of Ordovician limestone aquifer in Shendong Baode Coal Mine as the research background,based on the field exploration results,the lithology and porosity of the top stratum of Ordovician limestone aquifer are experimentally studied by using mineral composition analysis and indoor mercury injection test.The research results show that the rock mineral composition of the strata at the top of the Ordovician limestone aquifer is mainly calcite,with poor water absorption and permeability,poor pore structure,connected pores accounting for 5%~7% of the total pore volume,and the main pore diameter is 0.25 μ m.The pore characteristics reflect that the formation at the top of the Ordovician limestone aquifer has good water barrier.The research results provide an important reference for the research and evaluation of the water barrier performance of the strata at the top of the Ordovician limestone aquifer,and lay a foundation for the prevention and control of Ordovician limestone water damage in the floor of the mining area and other similar mining areas and the mining under pressure.