Patent ID: 11913319
Assignee: SAUDI ARABIAN OIL COMPANY
Field: Civil engineering (Other fields)
Classification: CPC E  C | IPC C  E

Claim 13:
14. A method of acidizing a sandstone formation in Earth crust, comprising:
pumping a first ammonium salt and a second ammonium salt through a wellbore into a subterranean formation, wherein the subterranean formation comprises the sandstone formation;
pumping a nitrite salt through the wellbore into the subterranean formation after conclusion of pumping the first ammonium salt and the second ammonium salt through the wellbore into a subterranean formation;
pumping an acid through the wellbore into the subterranean formation after conclusion of pumping the nitrite salt through the wellbore into the subterranean formation to give a mixture of water, the first ammonium salt, the second ammonium salt, the nitrite salt, and the acid in the sandstone formation;
generating heat, nitrogen gas, and hydrofluoric acid in the subterranean formation from reaction of the first ammonium salt and the second ammonium salt with the nitrite salt before the acid is pumped into the subterranean formation;
generating heat, nitrogen gas, and hydrofluoric acid in the subterranean formation from reaction of the first ammonium salt, the second ammonium salt, the nitrite salt, and the acid; and
acidizing the sandstone formation with the hydrofluoric acid as generated, wherein the acidizing comprises dissolving quartz in the sandstone formation with the hydrofluoric acid as generated.