侏罗纪煤田顶板含水层分布规律及防控技术

Distribution law and prevention and control technology of roof aquifer in Jurassic coalfield

侏罗系煤田是鄂尔多斯盆地的主要开采的煤田之一,上覆萨拉乌苏组、洛河组、直罗组砂岩体是地下水的主要蓄水层,研究清楚煤层与含水层的空间关系是实现采煤保水和水害防治的前提。煤层与地下水的空间关系受砂岩体的沉积作用和剥蚀作用控制,通过野外调查、文献搜集等手段分析了萨拉乌苏组、洛河组、直罗组的沉积和剥蚀作用,揭示了不同地层砂岩体的展布规律。结果表明,萨拉乌苏组砂体分布受古地形控制,呈“鸡窝”状分布;洛河组砂岩体受风积作用控制,侧向连续性强,上段渗透性优于下段;直罗组的砂岩体主要受辫状河沉积作用控制,河道砂体区域上呈定向条带状的透镜体展布,侧向不连续,地下水整体沿砂体定向渗流。根据不同地层砂体的展布规律,从区域水文地质角度提出的地下水防控措施,对区域煤炭资源合理开发,保护地下水,实现安全采煤具有重要大意义。

The Jurassic coalfield is one of the main mining coalfields in the Ordos Basin,and the sandstone bodies of the Sarausu Formation,Luohe Formation and Zhiluo Formation are the main aquifers of groundwater.Studying the spatial relationship between coal seams and aquifers is the premise for water-preserved coal mining and water hazard prevention.The spatial relationship between coal seam and groundwater is controlled by the sedimentation and erosion of sandstone bodies,and the sedimentation and erosion of Sarawusu Formation,Luohe Formation and Zhiluo Formation were analyzed by means of field investigation and literature collection,and the distribution law of sandstone bodies in different strata was revealed.The results showed that the distribution of sand bodies in the Sarausu Formation was controlled by paleotopography and distributed in the shape of“chicken nests”.The sandstone body of the Luohe Formation is controlled by aeolian action,with strong lateral continuity,and the permeability of the upper section is better than that of the lower section.The sandstone bodies of the Zhiluo Formation is mainly controlled by the sedimentation of the braided river,and the sand body of the river channel is distributed in a directional strip-like lens body,which is discontinuous laterally,and the groundwater as a whole flows directionally along the sand bodies.According to the distribution law of sand bodies in different strata,groundwater prevention and control measures are proposed from the perspective of regional hydrogeology,which is of great significance for the rational development of regional coal resources,the protection of groundwater,and the realization of safe coal mining.