Sulfomethylated lignite salt as a sacrifical agent in oil recovery processes

In a method for recovering oil from a subterranean formation containing oil and having an injection well and a production well wherein an aqueous anionic surfactant solution is injected into the injection well in order to drive the oil to the production well where it is produced the improvement which comprises:

• injecting into the injection well prior to the surfactant an aqueous solution of sulfomethylated lignite salt in an amount sufficient to adsorb on and occupy the active sites of the formation matrix and thereby diminish surfactant adsorption on said formation matrix.

In a method for recovering oil from a subterranean formation containing oil and having an injection well and a production well wherein an aqueous anionic surfactant solution is injected into the injection well in order to drive the oil to the production well wherein it is produced the improvement which comprises:

• injecting into the injection well in admixture with the surfactant sulfomethylated lignite salt in an amount sufficient to adsorb on and occupy the active sites of the formation matrix and thereby diminish surfactant adsorption on said formation matrix.

In a method for recovering oil from a subterranean formation containing oil and having an injection well and a production well wherein an aqueous surfactant solution comprising anionic and nonionic surfactants is injected into the injection well in order to drive the oil to the production well where it is produced the improvement which comprises:

• injecting into the injection well prior to the surfactant solution effective for enhancing oil displacement efficiency of the flooding water an aqueous solution of sulfomethylated lignite salt in an amount sufficient to adsorb on and occupy the active sites of the formation matrix and thereby diminish surfactant adsorption on said formation matrix.

In a method for recovering oil from a subterranean formation containing oil and having an injection well and a production well wherein an aqueous solution comprising anionic and nonionic surfactants is injected into the injection well in order to drive the oil to the production well wherein it is produced the improvement which comprises:

• injecting into the injection well in admixture with the surfactant solution sulfomethylated lignite salt in an amount sufficient to adsorb on and occupy the active sites of the formation matrix and thereby diminish surfactant adsorption on said formation matrix.