Shell Oil Comapny

George J Hirasaki

Richard E Dilgren

Hon C Lau

Jimmie B Lawson

Harold J Hill

Andrew H Falls

Derrill G Whitten

In a process in which steam and steam-foaming surfactant are injected into a subterranean reservoir having significant cation-exchange capacity, the rate of transport of the steam-foaming surfactant is increased by a prior injection of an aqueous liquid solution of surfactant and monovalent cation salt.

Reservoir preflushing process for increasing the rate of surfactant

In a process for injecting a steam-foam-forming mixture into a subterranean reservoir to displace oil, injecting a mixture containing only as much noncondensible gas as required for substantially reducing the mobility of an injected steam-foam-forming mixture containing a given kind and amount of surfactant and electrolyte, which amount of noncondensible gas to add is calculated from a specified equation interrelating the reservoir temperature and pore size.

Process for optimizing the noncondensible gas content of an

In a viscous oil reservoir in which the stratification of the rock permeability is insufficient to confine steam within the most permeable strata, oil can be produced by forming and expanding a steam channel through which steam is flowed and oil is produced. Steam is injected and fluid is produced at rates causing a steam channel to be extended between locations that are horizontally separated. A foam-forming mixture of steam, noncondensable gas and surfactant is then injected into the steam channel to provide foam and a relatively high pressure gradient within the channel, without plugging the channel. A flow of steam-containing fluid through the steam channel is continued in a manner such that the magnitudes of the pressure gradient, the rate of oil production, and the rate of steam channel expansion exceed those which could be provided by steam alone.

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Houston, TX, United States of America

George J Hirasaki