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

Claim 7:
8. A method of acidizing a sandstone formation, comprising:
pumping an ammonium salt not having fluoride, an ammonium salt having fluoride, and a nitrite salt through a wellbore into a subterranean formation in Earth crust, wherein the wellbore is formed through Earth surface into the subterranean formation, and wherein the subterranean formation comprises a sandstone formation;
generating heat, nitrogen gas, and hydrofluoric acid from reaction of the ammonium salt not having fluoride, an ammonium salt having fluoride, and the nitrile salt;
pumping an acid through the wellbore into the subterranean formation after conclusion of pumping the ammonium salt not having fluoride, an ammonium salt having fluoride, and a nitrite salt through the wellbore into the subterranean formation;
generating heat, nitrogen gas, and hydrofluoric acid from reaction of the ammonium salt not having fluoride, the ammonium salt having fluoride, the nitrite salt, and the acid; and
acidizing the sandstone formation with the hydrofluoric acid, wherein acidizing comprises dissolving quartz in the sandstone formation with the hydrofluoric acid as generated.