永川煤矿延深区须六段砂岩储层特征及致密气储量估算

Reservoir characteristics and estimating reserves of T₃X⁶ dense sandstone in Yongchuan coal mine

摘要: 永川煤矿延深区煤系地层上覆须家河六段岩层含有大量气体。在实验室对须六段岩芯进行了化验分析,结果显示为长石岩屑砂岩层,结构成熟度为中到低,孔隙度平均3.98%,渗透率平均0.080506×10^-3μm²,岩层内孔隙以微裂隙为主,含气饱和度平均84.3%,属于Ⅲ^Ⅱ类中等复合性储层类型的致密砂岩气藏。应用容积法计算表明该矿延深区须六段致密砂岩气地质储量为12.84×10⁸ m³,丰度为1.712×10⁸ m³/km²。可在井下应用水力压裂技术对岩层增透,结合瓦斯负压抽采系统,对须六段岩层致密气进行开发。

Abstract: The rock strata of T₃X⁶ dense sandstone in Yongchuan coal mine contain a large amount of gas.The result of laboratory assay shows that it is feldspar debris sandstone with medium to low structure maturity,3.98% porosity,0.080506×10^-3μm² permeability,gas saturation 84.3%,and the main pore structure in the inner layer is microfissure.So it belonging toⅢ ^Ⅱclass medium complex reservoir types of tight sandstone gas reservoirs.The calculation results show that the geological reserve of T₃X⁶ dense sandstone is 12.84×10⁸ m³,the abundances is 1.712×10⁸ m³/km².In general,we can increase the permeability by hydraulic fracturing technology,combined with negative pressure gas extraction system to development tight gas of T₃X⁶ dense sandstone.