针对华北型煤田下组煤开采奥灰水害威胁问题，以河东煤田保德煤矿峰峰组地层为研究对象，采用室内岩样薄片鉴定、微-CT扫描分析与现场压水试验相结合的手段，从微观-宏观多尺度分析了峰峰组岩性、孔隙结构以及渗透性特征，对其隔水性能进行了量化研究。研究表明:峰峰组地层岩性在垂向上存在明显差异性，上段岩性以泥晶、粉晶灰岩为主，总体呈晶粒结构，主要为泥晶方解石，部分为泥质结构，黏土质透镜体呈层状分布，下段岩性主要为粉质白云岩，晶间孔隙和溶孔多数被泥晶方解石和泥晶基质充填，岩石受到明显的压实、胶结和重结晶作用;峰峰组地层孔隙度为2.42%～3.18%，其中96.35%～96.74%的孔隙半径在2～8 μm，78.9%～87.6%的喉道半径在0.6～1.5 μm，孔隙与喉道半径分布集中且单一，总体表现为低孔隙性特征;峰峰组地层全段压水量为0.43～1.16 L/(m·min)，平均压水量0.95 L/(m·min)，透水率为0～2 L/(m·MPa·min)，压水量随深度呈现出逐步增高的趋势，峰峰组顶部压水量最小，进入峰峰组地层96.4 m深度压水量最大，变化趋势稍有波动，但总体较为平稳;采用霍斯列夫公式计算峰峰组全段渗透系数的数量级在10-3～10-4 m/d，总体呈现出弱透水性特征;从带(水)压开采角度，峰峰组全段可作为隔水层加以利用。

In order to evalute the water resisting property of the Fengfeng formation of Baode coal mine in Hedong Coalfield,the methods of thin section identification,micro CT scanning and field water pressure test were used.The characteristics of lithology,pore structure and permeability of the Fengfeng formation are revealed from micro macro multi scale.The research shows that the lithology of Fengfeng formation has obvious difference in vertical direction.The lithology of the upper strata mainly consists of argillaceous limestone and silty limestone,with grain structure,mainly consisting of argillaceous calcite and part of argillaceous structure.The clayey lens is distributed in layers.The lithology of the lower strata mainly consists of silty dolomite.Most of the intergranular pores and solution pores are filled by argillaceous calcite and argillaceous matrix.The rock is obviously compacted,cemented and recrystallized.The porosity of Fengfeng formation is about 2.42%-3.18%,in which 96.35%-96.74% of pore radius is between 2-8 μm,78.9%-87.6% of throat radius is between 0.6-1.5 μm,and the distribution of pore and throat radius is centralized and single,which is characterized by low porosity.The water pressure per unit length of the whole section of Fengfeng formation is 0.43-1.16 L/(m·min),the average water pressure is 0.95 L/(m·min),and the permeability rate is 0-2 L/(m·MPa·min).The water pressure value gradually increases with the depth.The water pressure value at the top of Fengfeng formation is the smallest,and the water pressure value at the depth of 96.4 m entering Fengfeng formation is the largest,with slight fluctuation,but the overall trend is relatively stable.The permeability coefficient calculated by the horslev formula is 10-3-10-4 m/d,showing the characteristics of weak permeability.The Fengfeng formation can be regarded as aquiclude.

1 研究区概况

2 峰峰组地层岩性特征

3 峰峰组地层孔隙结构特征

   3.1 孔喉网络三维分布特征

   3.2 孔喉网络连通性特征

   3.3 孔喉参数分析

4 峰峰组地层渗透性特征

   4.1 试验方法及过程

   4.2 试验成果分析

5 讨论

6 结论