Microemulsion to liquid crystal transition in two anionic surfactant systems
The phase behavior of two anionic surfactant systems, one containing a commercial alpha olefin sulfonate (AOS) and the other containing pure sodium dodecyl sulfate (SDS), was determined in the region where a transition from microemulsion to liquid-crystalline phases occurred with decreasing alcohol content and temperature. A general and rather complex pattern of phase behavior was seen that included a four-phase coexistence region of brine, microemulsion, lamellar liquid crystal, and oil, and two three-phase regions containing both microemulsion and liquid crystal. In much of the four-phase region, complete separation of the phases did not occur even after equilibration for 1 year or more at constant temperature. Instead, oil and brine were observed to coexist with stable birefringent dispersions that (for some compositions at least) apparently contained three phases: microemulsion, liquid crystal, and oil. Solubilization of brine was uniformly low in the phases making up the dispersions. The dispersions in the SDS system exhibited non-Newtonian behavior with apparent viscosities in the range of 50 to 100 mPa . s (50 to 100 cp) at a shear rate of 10 seconds/sup -1/. Microemulsion viscosities in the same system were about an order of magnitude lower. No plugging or other adverse behavior was seen when such dispersions flowed at a velocity of 10/sup -5/ m/s (3 ft/D) through a model porous medium having pore sizes comparable with those in reservoirs. In preliminary experiments, selected dispersions appeared to be capable of displacing oil from the same model porous medium.
- Research Organization:
- Vista Chem. Co., Ponca City, OK (US)
- OSTI ID:
- 6981092
- Journal Information:
- SPE (Society of Petroleum Engineers) Reserv. Eng.; (United States), Journal Name: SPE (Society of Petroleum Engineers) Reserv. Eng.; (United States) Vol. 3:3; ISSN SREEE
- Country of Publication:
- United States
- Language:
- English
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37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201 -- Chemical & Physicochemical Properties
ALKENES
BRINES
CALCULATION METHODS
CHEMICAL COMPOSITION
DISPLACEMENT FLUIDS
FLUID FLOW
FLUID INJECTION
FLUIDS
HYDROCARBONS
ITERATIVE METHODS
MATERIALS
MICROEMULSION FLOODING
MISCIBLE-PHASE DISPLACEMENT
NEWTON METHOD
OIL WELLS
ORGANIC COMPOUNDS
PHASE STUDIES
POROUS MATERIALS
STIMULATION
SURFACTANTS
TECHNOLOGY ASSESSMENT
VISCOSITY
WELL STIMULATION
WELLS