关键词: 煤岩, 煤层气, 地质特征, 资源量, 远景评价

Abstract: The major coal-bearing strata of Permian in East Yunnan and West Guizhou areas are Longtan formation of Upper Permian,which distributed in some coal-accumulated basins with complex anticline and syncline structures. The coal measures are well developed in this area with an area of coal-bearing strata of 2.58×10⁴km²,and dark metamorphism and thermal magma metamorphism. The coal evolution is in stage of maturity to over-maturity. The gas reserve is tremendous (13 078×10⁸m³) with good seal condition, gas generating capacity and good reservoir. The amount of coal-seam gas is mainly controlled by the depositional environment, coal evolution degree, burial depth, hydrologic condition and structural conditions. The gas reserve capacity is the essential factor controlling the gas-bearing amount in coal measures,which increases with the growth of coal ranks and burial depths ( the most distinct example is when the burial depth is less than 800 m). The gas bearing amount in coal beds is 10.0~18.8m³/t. For low-rank coal, the gas reserve capacity of fusinite coal beds is higher than that of vitrinite, while it is contrary for high-rank coal. For high vitrinite content, the coal beds have higher adsorption capacity and optimistic prospects for evaluation of this area.

Key words: coal-measure, coal-formed gas, geological characteristic, resource extent, prospective evaluation