Study on Conditions for Coalbed Methane Accumulation in Hegang Basin

摘要

The degree of metamorphism of coal seams in Hegang basin is mainly to medium coal rank. The macrolithotype of coal is rather excellent., given priority to half light type. In addition, there are a great number of thick coal seams in Hegang basin and the average thickness of the major coal seam can be more than 10 m. Furthermore its gas content is high, and it is superior in quality of coalbed methane and conditions for Generating coalbed methane. However the permeability of the reservoir changes a lot, the lithology is unfavourable in top and bottom of reservoir which is exactly in favor of local caprock sealing ability. There are two main differences in north and south of the basin, the coal rank and the preservation conditions. The coal rank and permeability of north is high, and it has developed favorable caprock. In contrary, the coal rank in south is low and it hasn't buried deeply enough. It also lack favorable caprock. Based on Comprehensive analysis on these factors, the conditions for coalbed methane accumulation is superior to the south. It is better to explore the north of Hegang basin firstly.