Reservoir preflushing process for increasing the rate of surfactant transport in displacing oil with injected steam and steam-foaming surfactant
This patent describes a process in which oil is displaced by injecting steam and steam-foaming surfactant into a reservoir in which the transporting of steam-foaming surfactant is impeded by a tendency of the reservoir rocks to exchange multivalent cations for monovalent cations in the injected aqueous liquid component of that mixture. An improvement is described which consists of: pretreating the reservoir, before injecting at least a portion of the steam and steam-foaming surfactant mixture, by injecting an effective volume of preflush aqueous liquid solution containing both a proportion of dissolved monovalent cation salt that exceeds the monovalent cation concentration which is effective for exchanging monovalent cations for multivalent cations on the reservoir rocks and an interfacial tension lowering surfactant, so that the preflush solution displaces multivalent cations out of the zone to be swept by steam and steam-foaming surfactant; and subsequently injecting a mixture of steam and steam-foaming surfactant into a relatively multivalent cation-depleted portion of the reservoir which was contacted by the preflush solution.
- Assignee:
- Shell Oil Co., Houston, TX
- Patent Number(s):
- US 4597442
- OSTI ID:
- 5400979
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
020300* -- Petroleum-- Drilling & Production
AQUEOUS SOLUTIONS
CATIONS
CHARGED PARTICLES
COLLOIDS
DISPERSIONS
ENERGY SOURCES
ENHANCED RECOVERY
FLUID INJECTION
FOAMS
FOSSIL FUELS
FUELS
ION EXCHANGE
IONS
MIXTURES
OIL WELLS
PETROLEUM
QUANTITY RATIO
RECOVERY
RESERVOIR ROCK
SALTS
SOLUTIONS
STEAM
STEAM INJECTION
STIMULATION
SURFACE PROPERTIES
SURFACE TENSION
SURFACTANTS
WELL STIMULATION
WELLS