Acid stimulation process for production from subterranean formations

Abstract

The present invention is a method to improve permeability of a formation in the vicinity of a production wellbore. An acid treatment composition is placed in the formation after a foaming composition is injected and a foam created from the foaming composition, thus forcing the acid treatment composition into less permeable strata. The foaming composition contains a sulfate surfactant as a foam stabilization agent. The sulfate hydrolyzes after a time period that is long enough to permit placement of the acid treatment composition. After the sulfate hydrolyzes, it becomes ineffective as a surfactant. Fluids produced from the formation after the acid treatment according to the present invention therefore do not contain significant concentrations of active surfactants, and therefore do not create foams or emulsions in surface separation equipment.

Dependencies are inferred from the claim text.