ALKOXYLATED SURFACTANT SYSTEM FOR HEAVY OIL RESERVOIRS

摘要

ALKOXYLATED SURFACTANT SYSTEM FOR HEAVY OIL RESERVOIRS (D#79,033-F) The invention is a method of recovering heavy oil from an underground reservoir by surfactant flooding which comprises injecting an aqueous surfactant solution comprising about 0.1% to about 5% by weight of an alkoxylated nonionic or ionic surfactant through an injection well into an underground reservoir containing a heavy oil having an average API gravity below about 20.degree. and a reservoir temperature above about 150.degree.F, where the alkoxylated surfactant must have sufficient alkylene oxide groups comprised of ethylene oxide or propylene oxide to have a cloud point above about 100.degree.F and below reservoir temperature, and to be water-soluble in the surfactant solution to be injected at a temperature below its cloud point, and have a sufficiently large hydrophobe to be soluble in the reservoir's heavy oil at a temperature equal to or greater than reservoir temperature. 79033.app