Hydrogels of graft polymers for acid diversion
AssigneeHalliburton Energy Services, Inc.
InventorsPratiksha Shivaji Meher, Ravikant S. Belakshe, Larry Steven Eoff
Life of this patent
Estimating the term…
Abstract
Methods, compositions, and systems that use hydrogels of graft polymers for diversion of acidic treatment fluids in subterranean formations. A method for acid diversion may comprise: applying a first acidizing treatment to a first treatment zone of a subterranean formation; introducing a hydrogel to the first treatment zone, wherein the hydrogel comprises a graft polymer that is crosslinked; and applying a second acidizing treatment to the subterranean formation, wherein the hydrogel diverts the second acidizing treatment to a second treatment zone.
Claims19
A method for acid diversion, comprising:
- applying a first acidizing treatment to a first treatment zone of a subterranean formation;
- introducing a hydrogel to the first treatment zone, wherein the hydrogel comprises a graft polymer, wherein the graft polymer comprises a biopolymer backbone and side chains grafted onto the biopolymer backbone, wherein the side chains comprise hydrophilic groups such that the graft polymer has the property of reduced absorption of water by at least 90% at pH 2 as compared to a neutral pH, and wherein the graft polymer is crosslinked;
- and
- applying a second acidizing treatment to the subterranean formation, wherein the hydrogel diverts the second acidizing treatment to a second treatment zone.
A method for acid diversion, comprising:
- introducing an acidic treatment fluid to a first treatment zone of a subterranean formation, wherein the acidic treatment fluid comprises an aqueous base fluid, an acid, and a hydrogel, wherein the hydrogel comprises a graft polymer comprising a biopolymer backbone and side chains grafted onto the biopolymer backbone, wherein the side chains comprise hydrophilic groups such that the graft polymer has the property of reduced absorption of water by at least 90% at pH 2 as compared to a neutral pH, and wherein the graft polymer is crosslinked;
- reacting the acid with acid-soluble materials in the first treatment zone such that pH of the acidic treatment fluid increases from an initial pH of about 2 or less to a pH of from about 2 to about 4 such that the hydrogel is activated;
- allowing the hydrogel to form a barrier to fluid flow in the first treatment zone;
- and
- diverting a subsequently introduced acidic treatment fluid to a second treatment zone in the subterranean formation.
A well system comprising:
- an acidic treatment fluid comprising an aqueous base fluid, an acid, and a hydrogel, wherein the hydrogel comprises a graft polymer comprising a biopolymer backbone and side chains grafted onto the biopolymer backbone, wherein the side chains comprise hydrophilic groups such that the graft polymer has the property of reduced absorption of water by at least 90% at pH 2 as compared to a neutral pH, and wherein the graft polymer is crosslinked;
- a fluid handling system comprising the acidic treatment fluid;
- and
- a conduit fluidically coupled to the fluid handling system and a wellbore.
Dependencies are inferred from the claim text.