Method of determining sodium chloride equivalency for improved oil recovery processes using surfactant compositions

Patent · Tue Sep 25 04:00:00 EDT 1984

OSTI ID:6142854

Hedges, J H

The sodium chloride equivalency of brine from a subterranean oil bearing reservoir is determined by equilibrating said brine with a known surfactant system and a standard hydrocarbon to give a multiphase system which is compared with known phase volume diagrams using the same ingredients at various sodium chloride concentrations to determine the salinity of the known systems at which the relative volumes correspond to those of the unknown system, this being the sodium chloride equivalency number of the unknown system. The above procedure can be used to allow use of standardized phase volume diagrams to tailor a surfactant system for a particular reservoir even though the reservoir does not have pure sodium chloride as the brine. In a more specific embodiment, the above system can be used even if the sodium chloride equivalency of the reservoir is quite high by utilizing as the cosurfactant an ethoxylated sulfated phenol and preparing a series of multiphase systems by equilibrating oil corresponding to that in the reservoir, a standard surfactant, and a series of ethoxylated sulfated phenol cosurfactants of varying degress of ethoxylation, all at the brine concentration of the reservoir to determine a system having an optimum salinity (i.e., where the volume of oil and water in the microemulsion phase is about equal) which is relatively low, i.e., about 1 percent. Thereafter, additional samples are prepared at higher surfactant concentrations, all of the other ingredients being equal and the resulting systems are used to displace oil from a test core, the results applied so as to determine the cosurfactant concentration at which maximum oil recovery is obtained.

• Assignee: Philips Petroleum Company
• Patent Number(s): US 4473116
• OSTI ID: 6142854
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
020300* -- Petroleum-- Drilling & Production
ALKALI METAL COMPOUNDS
BRINES
CHEMICAL COMPOSITION
CHLORIDES
CHLORINE COMPOUNDS
DIAGRAMS
DISPLACEMENT FLUIDS
ENHANCED RECOVERY
FLUID INJECTION
FLUIDS
HALIDES
HALOGEN COMPOUNDS
OIL WELLS
OPTIMIZATION
PHASE DIAGRAMS
RECOVERY
SALINITY
SODIUM CHLORIDES
SODIUM COMPOUNDS
SURFACTANTS
WATERFLOODING
WELLS