Methods for sealing high-permeability zones in subterranean formations
Methods for sealing high-permeability zones in subterranean formations are disclosed. The methods involve introducing a treatment fluid comprising polyacrylamide, acid, and water into a subterranean formation containing high- and low-permeability zones. The treatment fluid preferentially enters high-permeability zones, where polyacrylamide remains inactive in acidic conditions but swells upon neutralization, thereby at least partially sealing these zones. This sealing diverts subsequent fluid flow into low-permeability zones, enhancing hydrocarbon recovery. In formations with water-producing zones, the polyacrylamide selectively absorbs water, reducing unwanted water production. The treatment fluid may also include additives such as corrosion inhibitors, intensifiers, iron stabilizers, and chelants to improve operational performance. The disclosed methods provide controlled zonal coverage and improved stimulation efficiency in carbonate reservoirs.
1 . A method comprising:
introducing a treatment fluid to a subterranean formation comprising a high-permeability zone, a low-permeability zone, and a water-producing zone;
wherein the treatment fluid comprises a polyacrylamide, an acid, and water;
allowing the treatment fluid to enter the water-producing zone;
allowing the polyacrylamide to at least partially swell within the water-producing zone, thereby at least partially sealing the water-producing zone;
allowing the treatment fluid to enter the high-permeability zone;
allowing the polyacrylamide to at least partially swell within the high-permeability zone, thereby at least partially sealing the high-permeability zone;
diverting at least a portion of the treatment fluid to the low-permeability zone; and
allowing the acid to at least partially fracture the low-permeability zone.
2 . The method of claim 1 , wherein the treatment fluid further comprises a corrosion inhibitor, an intensifier, an iron stabilizer, a chelant, or any combination thereof.
3 . The method of claim 1 , wherein the treatment fluid has a concentration of the polyacrylamide of about 0.1 wt % to about 1 wt %.
4 . The method of claim 1 , wherein a pH of the treatment fluid prior to introducing the treatment fluid to the subterranean formation is about 0 to about 2.
5 . The method of claim 1 , wherein the subterranean formation comprises a carbonate mineral.
6 . The method of claim 1 , wherein the acid comprises hydrochloric acid.