Highly stable alcohol foams and methods of forming and using such foams

A method of treating a water-sensitive subterranean formation wherein a treating fluid foreign to the formation is introduced therein comprising the steps of:

• forming a foamed treating fluid having a vapor phase and having a liquid phase comprised of one or more alcohols or aqueous solutions thereof and a nonionic foam-forming surfactant or mixture of nonionic surfactants having the structural formula:
• ##STR7## wherein:
• x is an integer from 2-12 or an integer or fractional integer representing an average value of from 2-12;
• y and z are each individually an integer from 0-20 or an integer or fractional integer representing an average value of from 0-20;
• R and R.sub.1 are each individually hydrogen or an aliphatic hydrocarbon radical containing from 1-4 carbon atoms;
• and
• R.sub.2 is hydrogen or an ester group of the formula ##STR8## wherein R.sub.3 is an aliphatic hydrocarbon radical containing from 1-4 carbon atoms;
• and
• introducing said foamed treating fluid into said formation.

A method of fracturing a subterranean formation to stimulate the production of hydrocarbons therefrom comprising the steps of:

• forming a fracturing fluid comprised of a foam having a vapor phase and having a liquid phase comprised of one or more alcohols or aqueous solutions thereof and a nonionic foam-forming surfactant or mixture of nonionic surfactants represented by the structural formula:
• ##STR9## wherein:
• x is an integer from 2-12 or an integer or fractional integer representing an average value of from 2-12;
• y and z are each individually an integer from 0-20 or an integer or fractional integer representing an average value of from 0-20;
• R and R.sub.1 are each individually hydrogen or an aliphatic hydrocarbon radical containing from 1-4 carbon atoms;
• and
• R.sub.2 is hydrogen or an ester group of the formula ##STR10## wherein R.sub.3 is an aliphatic hydrocarbon radical containing from 1-4 carbon atoms;
• and
• introducing said foamed fracturing fluid into said formation whereby fractures are formed therein.

A highly stable high alcohol content foam comprised of:

• a liquid phase including an alcohol or mixture of alcohols and a foam-forming surfactant, said foam-forming surfactant being a nonionic surfactant or mixture of nonionic surfactants selected from the group represented by the formula:
• ##STR11## wherein:
• x is an integer from 2-12 or an integer or fractional integer representing an average value of from 2-12;
• y and z are each individually an integer from 0-20 or an integer or fractional integer representing an average value of from 0-20;
• R and R.sub.1 are each individually hydrogen or an aliphatic hydrocarbon radical containing from 1-4 carbon atoms;
• and
• R.sub.2 is hydrogen or an ester group of the formula ##STR12## wherein R.sub.3 is an aliphatic hydrocarbon radical containing from 1-4 carbon atoms;
• and
• a vapor phase.