The PermoCarboniferous source rocks are widely distributed in the Sulige region. With a flat regional structural relief and poor reservoir poroperm characteristics as background

the secondary migration of gas in the region is mainly driven by gas expansion. Gas charging potential is not only depended on the amount of gas expelled from the source rocks but also closely related to the thickness and porosity of the reservoirs to be charged. The author therefore proposes in the paper a quantitative method for gas charging potential evaluation by using reservoir charging index (RCI). Experimental results of two phase (gaswater) flow were also used to determine the evaluation standards of RCI at high

mediocre and low gas charging potentials respectively. For the PermoCarboniferous in Sulige Region

effective gas charging mainly occurs between the Carboniferous Benxi Formation and the 8th member of the Permian Shihezi Formation. Their RCI values are in the range from 0.4 to 0.6

indicating a medium to high gas charging potential as a whole.