The nature of colloid and interface of miscible phase system in alkaline-surfactant combination flooding

Several representative systems of surfactant + alkaline combination floodin g are chosen to study in this paper, these systems are characterized in two points: The first: oil is miscible with water only by reversing them five to ten times, this miscible process is close to spontaneous. Interfacial te nsion between oil and aqueous is ultra-low. The second: this type of system s is high dispersion and can be stabilized in a period of time. These syste ms are observed by microscopy, polarizing microscopy, microcalorimetry, las er particles analysis instrument and interfacial tension meter, it is found that small particles are main constituent and special liquid crystals dist ributed on the surface of small particles exist. Small particles and specia l liquid crystals are responsible for producing ultra-low interfacial tensi on. The middle phase microemulsion of sodium dodecylsulfate is studied. By comparing difference and similarity between middle phase microemulsion and miscible system, mechanisms of forming low interfacial tension in miscible system and middle phase microemulsion are discussed initially.