摘要
砂岩的微观孔隙结构特征决定了砂岩含水层的富水性、渗透性,砂岩含水层富水性预测是矿井防治水必须首先研究与解决的重要问题。以陕北侏罗纪煤田柠条塔煤矿为例,分别采集直罗组3块、延安组4块不同岩性典型砂岩样品,通过运用普通薄片、铸体薄片、高压压汞、核磁共振等实验测试技术,结合Matlab图像分析功能,研究了不同时代地层、不同岩性砂岩微观孔隙特征,联合高压压汞与核磁共振法获得孔喉半径分布,综合砂岩微观孔隙结构测试结果,将孔隙结构按照孔喉大小、分布及连通性的好坏依次划分为Ⅰ,Ⅱ,Ⅲ3种类型,对比钻孔抽水试验成果的钻孔单位涌水量,分析了砂岩微观孔隙结构与富水性之间存在的关系。研究结果表明:Ⅰ类孔隙结构较Ⅱ,Ⅲ类孔隙结构的粗粒与中粒砂岩比例高、排驱压力小、T2谱主峰的位置靠后;高压压汞与核磁共振所得孔隙半径分布基本一致;相同地层时代相同岩性条件下,风化程度越强,富水性越强;相同地层时代不同岩性条件下,粗、中粒砂岩较粉砂岩富水性强;不同地层时代相同岩性条件下,直罗组微观孔隙结构较好的Ⅰ类孔隙结构富水性强于延安组微观孔隙结构较差的Ⅱ类孔隙结构。
The microscopic pore structure characteristics of sandstone determine the water yield property and permeability of sandstone,and the prediction of water yield property of sandstone aquifer is an important problem that must be studied and solved firstly.Take Ningtiaota coal mine in Northern Shaaxi Jurassic coalfield as an example,this paper collected 7 typical sandstone samples of different lithology which include 3 blocks of Zhiluo Formation and 4 blocks of Yan’an Formation,and studied the microscopic pore structure characteristics of Zhiluo and Yan’an Formation with different lithology using experimental testing techniques that include thin section,cast thin section,high pressure mercury injection,nuclear magnetic resonance(NMR)and MATLAB image analysis.The distribution of pore throat radius was obtained by high pressure mercury injection and NMR.According to the pore throat size,distribution and condition of the continuity,the sandstone microscopic pore structure was divided into TypeⅠ,Ⅱ,Ⅲ.Comparing with the unit water inflow of borehole pumping test results,a certain relationship between the microscopic pore structure and aquifer water abundance was revealed.The results show that TypeⅠof pore structure has higher proportion of coarse and medium-grained sandstone,smaller displacement pressure,later position of T2 spectrum peak than that of TypeⅡ,Ⅲof pore structure.The distribution of pore radius obtained by high pressure mercury injection is basically consistent with that by nuclear magnetic resonance.Under the same stratigraphic age and lithology,the stronger the weathering degree is,the stronger the water abundance is.Coarse and medium-grained sandstone is stronger water abundance than siltstone under the same stratigraphic age and different lithology conditions.Under the same lithology conditions in different strata ages,the microscopic pore structure of Zhiluo Formation(the sandstone microscopic pore is TypeⅠ)is better than Yan’an formation(the sandstone microscopic pore is TypeⅡ),and the water abundance of Zhiluo formation is stronger than Yan’an formation.It provides a new idea for the characteristics and scientific prediction of water abundance of sandstone aquifer,and a technical support for mine water control and water resources protection.
作者
王苏健
冯洁
侯恩科
黄克军
薛卫峰
段会军
WANG Sujian;FENG Jie;HOU Enke;HUANG Kejun;XUE Weifeng;DUAN Huijun(Shaanxi Coal and Chemical Technology Institute Co.,Ltd.,Xi’an 710065,China;Department of Geology and Environment Engineering,Xi’an University of Science and Technology,Xi’an 710054,China;Innovation Team of “mining geology”for Sanqin Scholar,Xi’an 710065,China;Xi’an Research Institute of China Coal Technology & Engineering Group Corp,Xi’an 710077,China)
出处
《煤炭学报》
EI
CAS
CSCD
北大核心
2020年第9期3236-3244,共9页
Journal of China Coal Society
基金
国家重点基础研究发展计划(973)资助项目(2014CB047103)
国家自然科学基金面上资助项目(41472234)。
关键词
微观孔隙结构
砂岩含水层
富水性
高压压汞
核磁共振
microscopic pore structure
sandstone aquifer
water abundance
high pressure mercury injection
nuclear magnetic resonance
