Method for altering flow profile of a subterranean formation during acid stimulation

摘要

A method for acidizing a subterranean formation wherein a specific foam is used to block flow through the higher-permeable zones of the formation while the acid is being injected therein. The foam is generated from a surfactant solution comprised of a blend of surfactants comprised of a nonionic primary surfactant (e.g. ethoxylated alcohol or polyglycosides) a cationic co-surfactant (e.g. fluorinated quaternary ammonium chloride). A polymer (e.g. polysaccharides or partially hydrolyzed polyacrylamide) may be added to the surfactant solution to enhance the foam mobility reduction and a co-solvent (e.g. polyol) may be added if necessary to maintain the surfactant/polymer complex in solution.