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Micro-CT images (top panel) where colors indicate individual gas clusters, and respective pressure–volume curves (bottom panel) for the constant rate depletion experiments. Constant rate depletion leads to supersaturation where eventually gas nucleates which leads to instantaneous percolation. Upon re-pressurization eventually the percolation threshold is reached (left column). A quick drawdown below the bubble point leads to nucleation of gas bubbles, which – after immediate pressure increase near the bubble point – grow successively until they connect and in this way the percolation threshold i.e. the critical gas saturation is reached (right column) .