Sandstone stimulation
AssigneeSaudi Arabian Oil Company
InventorsAbdullah M. Al Alharith, Mohammed Ali Alyami
Life of this patent
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Abstract
Acidizing a sandstone formation in Earth crust, including pumping ammonium salts (an ammonium salt not having fluoride and an ammonium salt having fluoride) and nitrite salt through a wellbore into a sandstone formation, pumping an acid through the wellbore into the sandstone formation, generating heat, nitrogen gas, and hydrofluoric acid from reaction of the ammonium salts with the nitrite salt and the acid in the sandstone formation, and acidizing the sandstone formation with the hydrofluoric acid.
Claims20
A method of acidizing a sandstone formation in Earth crust, comprising:
- pumping ammonium salts and nitrite salt through a wellbore into a subterranean formation, wherein the subterranean formation comprises a sandstone formation, and wherein the ammonium salts comprise an ammonium salt not having fluoride and an ammonium salt having fluoride;
- generating heat, nitrogen gas, and hydrofluoric acid from reaction of the ammonium salts with the nitrite salt in the subterranean formation;
- pumping an acid through the wellbore into the subterranean formation after conclusion of pumping the ammonium salts and the nitrite salt through the wellbore into the subterranean formation;
- generating heat, nitrogen gas, and hydrofluoric acid from reaction of the ammonium salts with the nitrite salt and the acid in the subterranean formation;
- and
- acidizing the sandstone formation with the hydrofluoric acid, wherein the acidizing comprises dissolving quartz in the sandstone formation with the hydrofluoric acid.
(canceled)
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.
The method of claim 11, wherein pumping the ammonium salts and the nitrite salt comprises pumping the nitrite salt through the wellbore into the subterranean formation after conclusion of pumping the ammonium salts through the wellbore into the subterranean formation, and wherein pumping the ammonium salts and the nitrite salt into the subterranean formation and pumping the acid into the subterranean formation gives an in-situ aqueous mixture in the subterranean formation comprising the ammonium salt not having fluoride in a range of 10 weight percent (wt %) to 25 wt %, the ammonium salt having fluoride in a range of 1 wt % to 10 wt %, the nitrite salt in a range of 10 wt % to 25 wt %, and the acid in a range of 5 wt % to 20 wt %.
(canceled)
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.
Dependencies are inferred from the claim text.