Oil recovery process

Patent · Tue Dec 11 04:00:00 EST 1973

OSTI ID:7299625

Feuerbacher, D G; Smith, M K.H.

A process for waterflooding significantly reduces adsorption of the surfactant on the reservoir matrix. The process involves injecting a preflood containing a water soluble fluorine compound such as hydrofluoric acid or sodium fluoride into the reservoir in an amount sufficient to substantially satisfy all of the adsorption capacity of the reservoir rock. Following the preflood, any type of surfactant may be immediately injected; however, a nonionic surfactant such as ethylene oxide adduct of nonyl phenol is especially preferable. To the surfactant may be added a small amount of sacrificial preflush material to further aid in preventing adsorption. Sodium chloride may be added for the same purpose. The drive fluid, which is commonly water, is next injected to displace the oil and other fluids. Hydrofluoric acid cannot be used in calcareous formations such as limestone because of adverse reactions; however, sodium fluoride works well. When clays are present in a formation, relatively large amounts of fluoride compounds must be added to achieve the desired benefits. Polymers used for viscosity control, e.g., polyacrylamides, are subject to adsorption; therefore, a sacrificial inorganic fluoride compound may be added to the injection water along with the polymer in order to protect it from adsorption. Laboratory tests were performed on sand columns and indicate a significant reduction of surfactant adsorption when a fluorine containing preflush is employed.

• Assignee: Texaco Inc.
• Patent Number(s): US 3777818
• OSTI ID: 7299625
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
020300* -- Petroleum-- Drilling & Production
ADSORPTION
ALKALI METAL COMPOUNDS
ENERGY SOURCES
ENHANCED RECOVERY
FLUID INJECTION
FLUORIDES
FLUORINE COMPOUNDS
FOSSIL FUELS
FUELS
HALIDES
HALOGEN COMPOUNDS
HYDROFLUORIC ACID
HYDROGEN COMPOUNDS
INORGANIC ACIDS
OIL WELLS
PETROLEUM
SODIUM COMPOUNDS
SODIUM FLUORIDES
SORPTION
SURFACTANTS
WATERFLOODING
WELLS