Improved performance of crosslinked fracturing fluids comprising a nonionic surfactant

A method of treating an opening in a subterranean formation, the method comprising:

• providing a gel composition comprising a base fluid comprising a brine solution, a cross-linkable polymer soluble in the base fluid and a cross-linking agent;
• adding a nonionic ethylene oxide/propylene oxide (EO/PO) surfactant to the gel composition, the surfactant having a hydrocarbon chain in the range from C10 to C16;
• injecting the gel composition into the opening in the subterranean formation;
• cross-linking the gel composition;
• and
• increasing the size of the opening in the subterranean formation with the gel composition.

An uncrosslinked gel system or polymer or viscous fluid composition for use in a subterranean formation, the uncrosslinked gel system or polymer or viscous fluid composition comprising:

• a base fluid comprising a brine solution;
• a polymer or viscous fluid soluble in the base fluid;
• and
• a nonionic ethylene oxide/propylene oxide (EO/PO) surfactant having a hydrocarbon chain in the range from C10 to C16.