中奥陶统顶部地层富水性规律研究

Study on law of water-rich in top strata of Middle Ordovician

矿井11号煤层最低开采标高+230m,井田中奥陶统灰岩含水层水位标高+360m,煤层开采存在奥灰水带压开采问题,而11号煤层底板至中奥陶统顶面隔水层平均厚度20m,因而中奥陶统顶部峰峰组一段和上马家沟组三段地层的富水性,以及是否可以作为相对隔层利用,对煤层承压开采至关重要。通过水文钻探、放水试验和压水试验,分析了中奥陶统顶部地层的岩性特征、富水性特征、渗透性特征。综合试验结果表明,中奥陶统顶部地层主要以泥质白云岩、泥质灰岩为主,顶部18m地层隔水性能良好,揭露大部层段属弱富水性含水层,透水率小于10Lu,属极微透水至弱透水,为煤层承水压开采奠定有利的地质条件。

Minimum mining elevation of No.11 coal seam is +230 m,water level of middle Ordovician limestone aquifer is +360 m.There is pressure mining problem of Ordovician limestone water in coal seam mining,while the average thickness of water-proof seam from floor of No.11 coal seam to top of Middle Ordovician is 20 m,so the water-rich strata of the first member of Fengfeng Formation and the third member of Shangmagou Formation in the top of Middle Ordovician are rich in water.And whether it can be used as a relative barrier that very important for coal seam mining under confined pressure.Through hydrological drilling,drainage test and water pressure test,the lithological,water-rich and permeability characteristics of the top strata of the Middle Ordovician are analyzed.The comprehensive test results showed that the top strata of the Middle Ordovician were mainly argillaceous dolomite and argillaceous limestone,and the water-resisting property of the top strata was good.Most of the strata were weak water-rich aquifers with water permeability less than 10 Lu,which belonged to extremely weak water permeability to weak water permeability,thus laying a favorable geological condition for water-bearing mining of coal seams.