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

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.