High temperature polymer gels for well treatments and their use

A composition for use in treating a subterranean formation, the composition comprising:

• water;
• a water-soluble polymer of at least one of an acrylamide-containing polymer and a polyvinyl-alcohol-containing polymer;
• a crosslinking system comprised of 1) a primary crosslinking agent of at least one of a terephthalaldehyde source, dioxane, and trioxane, the primary crosslinking agent being used in an amount of about 0.2% to about 3% by weight of the composition;
• 2) hexamethylenetetramine in amount of about 0.005% to about 0.1% by weight to the composition;
• and 3) phenyl acetate in an amount of about 0.05% to about 3% by weight of the composition;
• and wherein
• the crosslinking system provides the composition a delayed gel time of about 2 to about 20 hours at temperatures of about 250° F. (121° C.) or higher.

A method of treating a subterranean formation penetrated by a wellbore, the method comprising:

• forming a treatment fluid composition comprising:
• water;
• a water-soluble polymer;
• a crosslinking system comprised of 1) primary crosslinking agent of at least one of a dialdehyde benzene source, a dioxane, and a trioxane, 2) a secondary low temperature organic crosslinking agent that generates aldehyde, and 3) a phenol source selected from the group consisting of phenyl acetate, hydroquinone, benzenediols, and combinations thereof;
• and wherein
• the crosslinking system provides a delayed gel time of the composition at temperatures of about 250° F. (121° C.) or higher of about 2 to about 20 hours;
• and
• introducing the treatment fluid into the formation through the wellbore.