Figure 4.
The image features two graphs related to gas pressure and injected gas volume in a porous stone sample. The left graph, labelled a, shows gas pressure measured in megapascals on the vertical axis, ranging from 0 to 10, plotted against time in days on the horizontal axis, ranging from 0 to 180. The graph includes annotations marking phases of gas injection, gas draining, and saturation, with distinct markers for two instances labelled first B T and second B T. The right graph, labelled b, presents the volume of injected gas measured in cubic centimetres, also plotted against time in days, with a range from 0 to approximately 0.35 cubic centimetres. Key annotations identify different models, Model A, Model B, and Model C, and highlight the completion of the first B T phase 2. The layout allows viewers to correlate variations in gas pressure with changes in injected gas volume over the defined time periods.Gas pressure on the boundaries during gas injection steps (a) and injected volume of gas during the first BT in Models A, B, and C (b)