Middle phase microemulsion to liquid crystal transition in surfactant systems for EOR
The phase behavior of two anionic surfactant systems, one containing a commercial alpha olefin sulfonate, and the other 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 decreasing temperature. A general and rather complex pattern of phase behavior was seen which 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 a year or more at constant temperature. Instead, oil and brine we observed to coexist with stable birefringent dispersions which, at least for some compositions, 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 50-100 mPa . s at a shear rate of 10 sec/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/day) through a model porous medium having pore sizes comparable to those in reservoirs. In preliminary experiments, selected dispersions appeared to be capable of displacing oil from the same model porous medium.
- Research Organization:
- Rice Univ.
- OSTI ID:
- 7159616
- Report Number(s):
- CONF-861080-
- Resource Relation:
- Conference: Society of Petroleum Engineers annual technical conference and exhibition, New Orleans, LA, USA, 5 Oct 1986
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
DISPLACEMENT FLUIDS
CRYSTAL-PHASE TRANSFORMATIONS
MICROEMULSIONS
OIL WELLS
MICROEMULSION FLOODING
PETROLEUM
ALCOHOLS
ALKENES
ANIONS
BRINES
CHEMICAL COMPOSITION
ENHANCED RECOVERY
EQUILIBRIUM
LIQUID CRYSTALS
MICROSTRUCTURE
PHASE STUDIES
POROSITY
RESERVOIR ROCK
SCALE MODELS
SIMULATION
SODIUM SULFATES
SULFONATES
SURFACTANTS
TEMPERATURE EFFECTS
VISCOSITY
WELL STIMULATION
ALKALI METAL COMPOUNDS
CHARGED PARTICLES
COLLOIDS
CRYSTAL STRUCTURE
CRYSTALS
DISPERSIONS
EMULSIONS
ENERGY SOURCES
FLUID INJECTION
FLUIDS
FOSSIL FUELS
FUELS
HYDROCARBONS
HYDROXY COMPOUNDS
IONS
LIQUIDS
MISCIBLE-PHASE DISPLACEMENT
ORGANIC COMPOUNDS
ORGANIC SULFUR COMPOUNDS
OXYGEN COMPOUNDS
PHASE TRANSFORMATIONS
RECOVERY
SODIUM COMPOUNDS
STIMULATION
STRUCTURAL MODELS
SULFATES
SULFUR COMPOUNDS
WELLS
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