Patent ID: 8720557

Claim:
A method of treating a zone of a subterranean carbonate formation penetrated by a wellbore, the method comprising the steps of: (a) forming a treatment fluid comprising: (i) water; (ii) a water-soluble polymer having at least one functional group that can be crosslinked with aluminum(III); and (iii) a water-soluble aluminum carboxylate; wherein the pH of the treatment fluid is less than 1; (b) introducing the treatment fluid through the wellbore into the zone; (c) allowing time for the pH of the treatment fluid to spend in the formation such that the pH of the fluid increases sufficiently for the aluminum to crosslink the polymer to form a crosslinked gel; (d) allowing time for the pH of the treatment fluid to continue to spend against the formation such that the pH of the crosslinked gel formed in the zone increases sufficiently to break the crosslinked gel, thereby reducing the viscosity of the crosslinked gel in the zone to a broken fluid; and (e) flowing back the broken fluid from the zone.