Compositions and methods for controlling strong acid systems

1. A method for controlling a rate of a reaction between an acid and a rock matrix during treatment of a subterranean formation that contains a hydrocarbon reservoir, the method comprising contacting the subterranean formation with an aqueous fluid that comprises a mixture of (a) an amount of a strong acid in a range of 10 Effective Weight Percent (Ewt %) to 20 Ewt %; and (b) an amount of a second acid or acid-generating compound in a range of 40% to 60% by weight, controlling an amount of free water in the aqueous fluid with the amount of strong acid and the amount of second acid or acid-generating compound, and thereby reducing a rate of reaction of the aqueous fluid with the rock matrix relative to the rate of the reaction of the aqueous fluid with the rock matrix absent the second acid or acid-generating compound,

wherein the strong acid is or comprises a mineral acid selected from hydrochloric acid (HCl), chloric acid (HClO3), hydrobromic acid (HBr), sulfuric acid (H2SO4), nitric acid (HNO3), perchloric acid (HClO4), hydroiodic acid (HI), phosphoric acid (H3PO4), or any combination thereof,

the second acid or acid-generating compound is or comprises an organic acid selected from formic acid, acetic acid, methanesulfonic acid, chloroacetic acid, dichloroacetic acid, trichloroacetic acid, fluoroacetic acid, difluoroacetic acid, trifluoroacetic acid, glutamic acid, diacetic acid, or any combination thereof, and

the rock matrix comprises carbonates, sandstone, shale, or any combinations thereof.

2. The method of claim 1 , wherein the organic acid is selected from methanesulfonic acid or glutamic acid diacetic acid.

3. The method of claim 1 , wherein the aqueous fluid further comprises a salt.

4. The method of claim 3 , wherein the salt is an inorganic salt.

5. The method of claim 3 , wherein the salt comprises CaCl 2 , NaCl, KCl, CaBr 2 , NaBr, KBr, calcium formate, or combinations thereof.

6. The method of claim 1 , wherein the aqueous fluid further comprises a chelant.

7. The method of claim 6 , wherein the chelant comprises phosphonic acid, 3-chloropropyl phosphonic acid, aminotris (methylene phosphonic acid) (ATMP), bis(hexamethylenetriaminepenta(methylene phosphonic acid) (BHMTPMPA), 1,2-cyclohexanediaminetetraacetic acid (CDTA), 1,4,7,10-tetraazacyclododec ane-1,4,7,10-tetraacetic acid (DOTA), 1,4,7,10-tetraazacyclodedecane-1,4,7,10-tetraphosphonic acid (DOTP), diethylenetriamineepentaacetic acid (DTPA), diethylenetriaminepenta (methylene phosphonic acid) (DTPMP), ethanol-diglycinic acid (EDG), ethylenediamineteraacetic acid (EDTA), ethylene diamine tetra (methylene phosphonic acid) (EDTMPA), ethylenedioxybis(ethyliminodi(acetic acid)) (EGTA), L-glutamic acid N,N-diacetic acid, tetra sodium salt (GLDA), hydroxyaminocarboxylic acid (HACA), 1-hydroxyethane 1,1-diphosphonic acid (HEDP), N-hydroxyethyl-ethylenediamine-triacetic acid (HEDTA), hydroxyethyleneiminodiacetate (HEIDA), N″-carboxymethyldiethylenetriamine-N,N,N′,N″-tetraacetate (HDTPA), iminodiacetic acid (IDA), methylglycinediacetic acid (MGDA), N,N′-bis(carboxymethyl)glycine (NTA), nitrolotripropionic acid (NTP), nitrilotrimethylenephosphonic acid (NTMP), sodium hexametaphosphate (SHMP), tetraammonium EDTA, triethylenetetramine-N,N,N′,N″,N′″,N′″-hexaacetic acid (and N,N′-bis(butanamide) derivative) (TTHA), terpyridine, bypyridiene, triethylenetetramine, biethylenetriamine, bis(hexamethylenetriamine) (BHMT), or derivatives or mixtures thereof.

8. The method of claim 1 , wherein the amount of the strong acid in the aqueous fluid is in the range of 11 Effective Weight Percent (Ewt %) to 19 Effective Weight Percent (Ewt %).

9. The method of claim 1 , wherein the organic acid is present in the aqueous fluid at a concentration in the range of 42 wt % to 54 wt %.

10. The method of claim 1 , wherein the step of contacting comprises introducing the aqueous fluid into the subterranean formation via coiled tubing or bull heading in production tubing, casing, or drilling pipes.

11. The method of claim 1 , wherein the aqueous fluid further comprises a surfactant.

12. The method of claim 1 , wherein the aqueous fluid further comprises one or more of gelling agent.

13. The method of claim 1 , wherein the strong acid is hydrochloric acid (HCl).