Investigating Supercritical CO2 Foam Propagation Distance: Conversion from Strong Foam to Weak Foam vs. Gravity Segregation

• Published in: Transport in porous media Vol. 131; no. 1; pp. 223 - 250
• Main Authors: Izadi, M., Kam, S. I.
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Netherlands 2020; Springer Nature B.V
• Subjects: Carbon dioxide; Civil Engineering; Classical and Continuum Physics; Computer simulation; Conversion; Earth and Environmental Science; Earth Sciences; Foams; Geotechnical Engineering & Applied Earth Sciences; Gravitation; Hydrogeology; Hydrology/Water Resources; Industrial Chemistry/Chemical Engineering; Mathematical models; Propagation; Reservoirs; Gravity segregation; Population balance model; CO; foam; Foam propagation
• ISSN: 0169-3913; 1573-1634
• DOI: 10.1007/s11242-018-1125-z

This study investigates how to determine the optimal supercritical CO 2 foam injection strategies, in terms of total injection rate (or injection pressure, equivalently) and injection foam quality, to place injected foams deep and far into the reservoir. Two different mechanisms that limit field foam propagation, such as “conversion from strong foam to weak foam” and “gravity segregation,” are examined separately, and the results are combined together. The first is performed by using a mechanistic foam model based on bubble population balance, while the second is conducted by an analytical model (called Stone and Jenkins model) and reservoir simulations with a commercial software (CMG-STARS). Note that the gas-phase mobility, required as a key input parameter for gravity segregation simulations, is calibrated by the mechanistic model, which is a significant advance in this study. The results from both mechanisms show in general that foam propagation distance increases with increasing injection pressure or rate (which is often limited by the formation fracturing pressure) and increases with decreasing foam quality down to a certain threshold foam quality below which the distance is not sensitive to foam quality any longer. It is found that the mobilization pressure gradient (i.e., the pressure gradient above which foam films are mobilized to create a population of bubbles) plays a key role to determine the distance. Therefore, the injection of supercritical CO 2 foams with lower mobilization pressure gradient should be more favored in field applications. As a step prior to real-world reservoir applications, this study deals with a relatively ideal reservoir (i.e., large homogeneous cylindrical reservoir) focusing on the steady state after foam treatment in the absence of oil.