{'fraction_non_alphanumeric': 0.02336145360155743, 'fraction_numerical': 0.00973393900064893, 'mean_word_length': 4.976744186046512, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Determining Gas Re-Mobilization and Critical Saturation: From Field Scale CO2 Injection Experiments to Pore-Scale Modelling

Residual Trapping of CO 2 , characterized quantitively by the residual saturation (S gr ), is one of the main trapping mechanisms in geological storage of CO 2 (GCS) [1,2].The long-term stability of residual trapping is, however, not very well understood. The remobilization of the gas in cases where saturation is increasing due to pressure depletion, rather than gas injection, has not been extensively studied. Pressure depletion may occur due to any type of leakage or simply dissipation of near-well pressure build-up. As this occurs, the trapped CO 2 gas phase expands and simultaneously some of the dissolved CO 2 exsolves from the aqueous phase, both processes leading to an increased CO 2 saturation [3]. This type of remobilization is not commonly addressed in numerical modelling studies. Conventional theories of fluid flow in porous media predict that CO 2 phase is remobilized and is no longer trapped at saturations higher than the residual saturation S gr . However, already in 1988 Fishlock et al. [4] stated that observed gas mobilization during pressure depletion could not be explained by this traditional theory. They conducted a series of laboratory experiments in the context of waterflooding of condensate gas reservoirs and enhanced gas recovery and found that the trapped gas becomes mobile at a saturation which was higher than S gr , which value was then named the critical gas saturation