Influences of depositional environment on reservoir space of coal in Hegang Coalfield

in order to discover the effect of deposiional environment on reservoir space of coal,pore and fracture characteristics and formationenvironment of coal in Chengzihe Formation of Hegang Coalfeld were systematcally analyzed using a series of analytical methods including scanning electron microscope,ow temperature nitrogen adsorption and cluster analysis.The results showed that there were four types of pore models in Hegang Coalfield. From Model l to Model V,the pore morphology and typesof fissure gradually became diversified.Meanwhile,with the increase of pore adsorption capacity.desorption became more dficut.Coal facies analysis revealed that from south to north the overying water deepened and the speed of burial accelerated during main coal-forming period of Hegang Coalield. Fan-delta was the main coal accumulating environment and the thickness and stability of coal seam in the north were superior to the south.The depositional environment had a certain infuence onpore structure and fracture development.From north to south,increasing ash content and more complicated pore system were observed and thenumber and types of fracture gradually diversified. t is concluded that the reservoir space of the south is more complex than the north and the porosity and permeability of the south are larger than the north.