神东矿区不同埋深弱胶结砂岩的孔隙结构特征研究

Pore structure characteristics of weakly cemented sandstone with different buried depths in Shendong mining area

为了研究神东矿区不同埋深弱胶结砂岩的孔隙结构特征,以布尔台煤矿4种不同埋深弱胶结砂岩为研究对象,运用低场核磁共振测试仪对4种不同埋深试样进行了测试,分析了不同埋深弱胶结砂岩的T_(2)谱特征、孔径分布和孔喉分布。研究结果表明:4种不同埋深弱胶结砂岩(92.14~94.30 m,118.40~120.69 m,242.27~242.95 m,317.86~320.33 m)的T_(2)谱特征、孔径分布和孔喉分布存在差异,孔隙率分别为39.180%、36.132%、44.782%、19.732%;T_(2)谱由3个波峰逐渐转变为2个波峰,波形连续性好(孔隙连通性好);弱胶结砂岩的孔径可以分为5类:微孔、小孔、中孔、大孔和微裂隙,孔径以中小孔为主,大孔次之;弱胶结砂岩的孔喉半径以0~0.10μm为主,0.10~0.16μm次之。研究成果有助于进一步揭示我国西部地区工作面溃水溃沙的机理。

In order to study the pore structure characteristics of weakly cemented sandstones with different buried depths in Shendong mining area,four kinds of weakly cemented sandstones with different buried depths in Buertai coal mine are taken as the research objects.Four kinds of samples with different buried depth were tested by low field NMR.The T_(2) spectrum characteristics,pore size distribution and pore throat distribution of weakly cemented sandstone with different buried depths are analyzed.The results show that there are differences in T_(2) spectrum characteristics,pore size distribution and pore throat distribution of four weakly cemented sandstones with different buried depths(92.14-94.30 m,118.40-120.69 m,242.27-242.95 m,317.86-320.33 m).The porosity of four weakly cemented sandstones with different buried depths are 39.180%,36.132%,44.782%and 19.732%,respectively.T_(2) spectrum gradually changed from three peaks to two peaks,with good continuity(good pore connectivity).The pore size of weakly cemented sandstone can be divided into five types:micropore,small pore,medium pore,large pore and microfissure.The pore size is mainly small and medium-sized pore,followed by large pore.The pore throat radius of weakly cemented sandstone is mainly 0-0.10μm,followed by 0.10-0.16μm.The research results are helpful to further reveal the mechanism of water and sediment break in working face in western China.