SOLUBILIZED OIL-WATER SOLUTIONS SUITABLE FOR MISCIBLE FLOODING

摘要

Solubilized oil-water solutions suitable for use in miscible flooding and injection well clean-out methods are prepared from an alkali metal petroleum sulfonate containing free mineral oil and/or crude oil, a cosurfactant or coupling agent such as the ethylene oxide adducts of 4 to 10 carbon atom primary alcohols and a mono-valent ion brine solution having a solids concentration not greater than about 60,000 parts per million. Such solubilized oil-water systems when introduced in the form of a slug into an oil bearing reservoir and displaced through the latter tend to dissolve oil into and reject water from the leading edge of the slug thus creating a gradation of viscosity which increases from the leading edge to the trailing edge of the slug thereby aiding in preventing bypassing of the driving water around the slug during flooding operations. The ratio of sulfonate to cosurfactant employed in these compositions ranges from 1:9 to 7:3.