Aqueous petroleum sulfonate mixture and method of use in post- primary oil recovery

摘要

An aqueous mixture is made of water, oil containing petroleum sulfonate, inorganic salt and, optionally, polymeric material wherein the polymeric material is added when it is desired to increase the viscosity of the mixture so that it is more suitable for use in certain types of oil recovery processes. The oil-to-active petroleum sulfonate ratio is adjusted to a preferred amount and oil in the petroleum sulfonate can be extracted and another oil can be added to replace the extracted oil so that the mixture has an increased tolerance to inorganic salt.