Surfactant Concentration for Foam Formation and Propagation in Snorre Reservoir Core

Foam floods were conducted in an oil-free Snorre field core with C14-16AOS surfactant and methane or Snorre field gas, at 90°C and 300 bar. The lowest surfactant concentration at which foam was generated overlapped the cmc region. Concentrations exceeding the cmc were required to propagate the foam, independently of surfactant adsorption. Once formed and propagated, the foam could be maintained for prolonged periods of gas/liquid co-injection at sub-cmc or zero surfactant concentrations.