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This study analysis the behavior of CO₂ hydrate formation in porous media under dynamic flow conditions, based on the effects of water salinity and temperature variation. Experiments were performed in fresh water and brine-saturated cores at temperatures ranging from 1°C to 3°C with a varying CO₂ injection flowrate of 20, 30, 40 ml/min.
Experimental results illustrate that in fresh water-saturated cores, CO₂ hydrate formation required higher pressure in dynamic conditions compared to static conditions. At 1°C, hydrate formed at 395 psi under dynamic flow, nearly 2.20 times higher than the static condition pressure of 180 psi. With increasing temperature, this pressure ratio decreased gradually, reaching 2.05 at 2°C (static: 220 psi; dynamic: 450 psi) and further to 1.96 at 3°C (static: 275 psi; dynamic: 540 psi). This proportion explains that higher temperatures reduce hydrate formation tendency and plugging severity.
Due to the inhibitory effect of salinity at 3°C, hydrate formation pressure in brine-saturated cores increased to 690 psi, which is 1.27 times higher than in fresh water. The salts present in brine solution lowered water activity and hindered hydrate nucleation, requiring additional pressure for hydrate formation.
This study provides valuable insights for designing CO₂ sequestration operations, emphasizing the importance of temperature, salinity, and flow conditions in controlling hydrate formation and mitigating flow assurance challenges in subsurface storage.