Abstract: Addition of small amounts of water and small amounts of neutral oleophilic organic compounds, e.g., alcohols, phenols, aldehydes, ketones, and esters to product mixtures produced by treatment of hydrocarbons with sulfur trioxide, followed by neutralization with an inorganic hydroxide, and comprising oleophilic petroleum sulfonates, together with undesired hydrophilic petroleum sulfonates and inorganic salts, causes separation of a lower phase containing substantial quantities of said undesired constituents and permitting ready recovery of said oleophilic hydrocarbon sulfonates. The products are particularly useful in micellar systems for the secondary-type recovery of petroleum.

Abstract: Micellar systems which are neither oil-external nor water-external can be formed from petroleum sulfonates, e.g., crude oil sulfonates formulated with water and, optionally, cosurfactants, e.g., hexanol. Because such micellar systems resist uptake of both oil and water, they are suitable for long distance displacement in which injection wells are spaced at least about 300 feet from production wells.