Comparative analysis of physical properties of deep and shallow CBM reservoirs in Junggar Basin
In order to investigate the differences in deep and shallow CBM occurrence,coal samples were collected from boreholes at depths of over 1 500 m and below 1 500 m in the Junggar Basin coal mine.Through data collection and laboratory testing,the variations in physical properties of deep and shallow coal reservoirs in the research area were analyzed,leading to the following conclusions:vitrinite content of deep-buried coal was higher than that of shallow-buried coal,with a more intact coal structure and stronger reservoir modification;deep-buried coal had a higher gas content than the shallow-buried coal and the CBM occurrence state gradually changed from undersaturation to supersaturation,with diverse gas origins;the permeability pores of shallow-buried coal were more developed than those of deep-buried coal,while the adsorption pores in deep-buried coal were more developed than those in shallow coal rock.The shallow-buried coal rocks were primarily characterized by externally generated fractures with good connectivity between pore fractures,while deep-buried coal rocks were dominated by internally generated fractures with mineral-filled fractures,and deep porosity and fracture density were smaller than those in the shallow part,resulting in poorer permeability.Comparative results indicated that the deep part of the Junggar Basin had better CBM enrichment than the shallow part,with significant development potential.However,the permeability of deep CBM reservoir was much lower than that in the deep part,posing challenges to development.Therefore,it was recommended to promote deep CBM development through a combination method of fracturing transformation and drainage gas extraction technologies.
the Junggar Basindeep coal reservoirshallow coal reservoirphysical propertiesCBM development
NETL
NSTL
万方数据
