IN-SITU CROSSLINKING AND CALCIUM ION COMPLEXATION FOR ACIDIZING A SUBTERRANEAN FORMATION.

摘要

A method of treating a zone of a subterranean formation penetrated by a wellbore, the method including the steps of: (a) forming a treatment fluid comprising: (i) water; (ii) a strong acid); (iii) a water-soluble polymer having at least one functional group that can be crosslinked with aluminum(III); (iv) a water-soluble aluminum carboxylate; and (v) a complexion agent for calcium ions; wherein the pH of the treatment fluid is less than the pH required for the aluminum to crosslink the polymer to form a crosslinked gel; (b) introducing the treatment fluid through the wellbore into the zone; and (c) allowing time for the strong acid in the treatment fluid to spend in the formation such that the pH of the fluid increases sufficiently for the aluminum of the aluminum carboxylate to crosslink the polymer.