Hydraulic fracturing in subterranean formations

Abstract

This invention provides a process for the hydraulic fracturing of a subterranean formation, which comprises introducing into the formation under fracturing pressure a fracturing fluid comprising solid particulate suspended in a fluid dispersion comprising water, a specified gaseous or supercritical component, and a surfactant component selected from a certain class of polysaccharide compounds. For purposes of this invention, the gaseous or supercritical carbon dioxide and gaseous nitrogen, carbon dioxide and C.sub.1 to C.sub.3 hydrocarbons, and mixtures thereof. The polysaccharide component comprises one or more surfactants of the formula RO(R.sup.1 O).sub.x Sacc.sub.z, wherein R is a monovalent organic radical having a carbon number in the range from about 7 to 24, R.sup.1 represents a divalent hydrocarbon radical containing from about 2 to about 4 carbon atoms, x is a number having an average value in the range from 0 to about 12.0, and Sacc.sub.z represents an average number z between about 0.7 and 10.0 of moieties derived from reducing saccharides containing 5 or 6 carbon atoms. R preferably represents an alkyl, alkylphenyl, hydroxyalkyl phenyl, or hydroxyalkyl moiety having a carbon number in the range from about 8 to about 20; the optional (R.sup.1 O) group is (when present) preferably an oxyethylene group; x is preferably between about 0 and 8.0, and is most preferably 0; Sacc preferably represents a glucose, galactose, glucosyl or galactosyl residue, and most preferably represents a glucose residue; and z is suitably between about 0.7 and 10.0, and is most preferably between about 1.3 and 4.0. Seawater and brines suitably serve as the source of the water. Dispersions formed from these three components are viscous foams which are highly stable under the conditions typically encountered in applications of hydraulic fracturing processes.