Patent ID: 6715553
Filing Date: 2004-04-06
Classification: C09K

Abstract:
An improved method of generating gas in and foaming an alkaline aqueous well fluid such as an aqueous drilling fluid, an aqueous spacer fluid and the like introduced into a subterranean zone penetrated by a well bore comprising the steps of:(a) combining with said alkaline aqueous well fluid one or more gas generating chemicals present in said aqueous well fluid in an amount in the range of from about 10% to about 100% by weight of water in said aqueous well fluid and a mixture of foaming and foam stabilizing surfactants whereby said gas generating chemical or chemicals react with said alkaline aqueous well fluid and gas and foam are formed in said well fluid while it is being pumped; and (b) pumping said alkaline aqueous well fluid formed in step (a) into said well bore and said subterranean zone.