Acidizing of subterranean formation using in-situ generated hf

A method of acidizing a subterranean formation surrounding a wellbore, the method comprising:

• injecting an acid generating component and a heat generating component simultaneously into the wellbore,
• wherein:
• the acid generating component comprises a first aqueous solution comprising ammonium fluoride, and a second aqueous solution comprising an oxidizing agent;
• the heat generating component comprises a third aqueous solution comprising an ammonium salt that is not ammonium fluoride, and a fourth aqueous solution comprising a nitrite salt;
• a molar ratio of ammonium fluoride to the oxidizing agent is in a range of 1:1 to 8:1;
• a molar ratio of ammonium ions present in the ammonium salt to the nitrite ions present in the nitrite salt is in a range of 1:4 to 4:1;
• and
• a molar ratio of the ammonium fluoride to the nitrite salt is in a range of 1:1 to 10:1,
• whereby the ammonium salt reacts with the nitrite salt to release heat and nitrogen gas, and the heat initiates a reaction between ammonium fluoride and the oxidizing agent thereby forming hydrogen fluoride within the subterranean formation.