Abstract:

CO₂ foam is constantly generated and destroyed during the process of flowing in the reservoir, and the gas channeling capacity of foam depends on its stability which is an important evaluation index of foam flooding. A method based on multiple light scattering to study the stability of foam has been established, in which the small changes in foam defoaming and liquid drainage in different periods can be reflected by the intensity changes of transmitted light and backscattered light. The microscopic mechanisms of foam collapse were explored, and a method for quantitatively calculating the half-life of a foam system by TSI was proposed. In addition, the CO₂ foam stabilized by anionic-nonionic surfactant SS163 and its mixture with nanoparticles were prepared, and the foam stability was compared by multiple light scattering method and Warning-Blender method. The results demonstrate that multiple light scattering method has advantages such as more precise temperature control and no influence of external air flow, which is a foam evaluation method with high accuracy and repeatability.

Key words: CO₂ foam, multiple light scattering, foam stability, TSI index