Dynamic evolution of steam channeling in porous media and response mechanism of two plugging systems

In this paper, the loose sandstone is used as the porous medium model, and the formation and evolution of steam channeling channels and the response mechanism of two different plugging systems to channeling are systematically studied. First, the effects of steam injection rate, steam temperature, and pore pressure on the evolution characteristics of core permeability, porosity, and pore structure were quantitatively characterized by a high-temperature and high-pressure dynamic reactor and nuclear magnetic resonance T2 spectrum, respectively. The mechanical mechanism of permeability contrast as the core control variable of steam channeling instability was revealed. Second, the visualization experiment of steam channeling was carried out by using the high-temperature and high-pressure visual physical simulation device. The two-way flow phenomenon of the top steam overlapping upward and the bottom condensate water migrating downward was observed. This behavior was interpreted as a two-way fingering (steam-water double channeling) mode driven by a density difference. Finally, the mechanical response of the two plugging systems to channeling was quantified by nitrogen foam (Jiamin effect plugging high-permeability channels) and thermosetting plugging agent (mobility control) experiments: the vertical/plane recovery degree increased by 45.31/17.10 percentage points, respectively.