ABSTRACT
Moore (2012) reviewed related researches about coalbed originated methane gas. He mentioned the differences between gasses in rock formations (clastic gasses) and gasses originated in coalbeds (coal seams or carbon based gases). Coal seams in general have biogenic and thermogenic methane gasses and coal ranks usually provide clue about the type of methane. Coalbeds having high rank coal (usually older coalbeds) have thermogenetic methane gasses. Moore (2012) wrote also that “the presence of methane in coal seams has long been recognized, first as a hazard and but more lately as an economically harvestable commodity”. Economical value of methane attracts more researchers to understand the methane origination and migration parameters. When methane origination during coalification is determined in more detail, its migration properties and reservoir characteristics are also well described. According to Moore (2012) surface of coal seam pores and joints (discontinuities) are the methane bearing locations, therefore coal seam porosity, permeability and discontinuity analyses should have been achieved to obtain coalbed methane conditions. Methane gas originated in coal beds may have emitted to atmosphere through permeable overburden rock formations. Faults, fault fillings and discontinuity
parameters are all influencing factors to get permeable or impermeable rock formations. If some part of methane originated by coalification process detained and hold in coalbeds or surrounding rock formations, mine engineers have to localize their position. Firstly, it is commercial commodity for gas producing companies; secondly, it can form gassy coalbed conditions which are very dangerous for mining operations.
