Figure 1

Snap-off during imbibition in a throat between two adjacent pores. Various times during brine injection showing oil progression and trapping in a water-wet Ketton rock sample: (a) t = 24 min 4 s (injected volume = 1.077 µL), (b) t = 42 min 26 s (injected volume = 1.899 µL), (c) t = 43 min 4 s (injected volume = 1.927 µL), (d) t = 46 min 14 s (injected volume = 2.069 µL), (e) t = 47 min 30 s (injected volume = 2.126 µL), (f) t = 53 min 50 s (injected volume = 2.409 µL, (g) t = 60 min 48 s (injected volume = 2.721 µL), and (h) t = 61 min 26 s (injected volume = 2.749 µL). The rock and brine are shown semi-transparent and transparent respectively for effective visualization. The dashed blue arrows indicate the approximate direction of interface migration. Points A–C show the events marked in Fig. 2. Time ‘t = 0’ denotes the start of the imbibition process (after acquiring the first tomographic image in imbibition). Time (t) represents the end of each tomographic image acquisition.