Thermally activated strong acids
View Patent ↗An acid-generating fluid comprising a thermally activated strong acid precursor is provided in the method of the present invention. The thermally activated strong acid precursor comprises sulfur dioxide or a first precursor of a compound adapted to react to liberate sulfur dioxide, and an aldehyde and/or a ketone or a second precursor of a compound adapted to react to liberate an aldehyde and/or ketone. The acid-generating fluid is placed into a subterranean formation, where the first precursor and/or the second precursor are thermally activated, thereby liberating sulfur dioxide and the aldehyde and/or ketone. The sulfur dioxide and the aldehyde and/or ketone are reacted to form a thermally activated strong acid.
1. A method comprising:
providing an acid-generating fluid that comprises water and a thermally activated strong acid precursor, the thermally activated strong acid precursor comprising
a first precursor of a compound adapted to react to liberate sulfur dioxide, and
a second precursor of a compound adapted to react to liberate a component selected from aldehydes, ketones, and combinations thereof;
placing the acid-generating fluid into a subterranean formation;
thermally activating the first precursor and the second precursor, thereby liberating sulfur dioxide and the component selected from aldehydes, ketones, and combinations thereof; and
reacting the sulfur dioxide and the component selected from aldehydes, ketones, and combinations thereof to form a thermally activated strong acid.
2. The method of claim 1 , wherein the first precursor is selected from the group consisting of a sulfone adduct of butadiene, a sulfone adduct of piperylene, a sulfone adduct of isoprene, a sulfite ester, and combinations thereof.
3. The method of claim 1 , wherein the first precursor is selected from the group consisting of ethylene sulfite, dimethyl sulfite and combinations thereof.
4. The method of claim 1 , wherein the second precursor is selected from the group consisting of paraformaldehyde, polyoxymethylene, metaldehyde, trioxane, formaldehyde, acetaldehyde, and combinations thereof.
5. The method of claim 1 , wherein the first and second precursors are provided in a ratio of 1:1.
6. The method of claim 1 , wherein the first and second precursors are provided in an amount sufficient to generate a strong acid at a concentration of from 0.1% to 10% by weight of the acid-generating fluid.
7. The method of claim 1 , wherein the thermally activated strong acid precursor comprises an SO 2 precursor and an aldehyde or ketone precursor in an amount sufficient to generate a strong acid at a concentration of from 1% to 5% by weight of the acid-generating fluid.
8. The method of claim 1 , wherein the acid-generating fluid further comprises a dienophile.
9. The method of claim 8 , wherein the dieneophile and the thermally activated strong acid precursor are provided in a 1:1 molar ratio.
10. The method of claim 1 , wherein the acid-generating fluid further comprises a base.
11. The method of claim 10 , wherein the base is CaCO3.
12. The method of claim 1 , wherein the acid-generating fluid is an emulsion.
13. The method of claim 1 , wherein the acid-generating fluid has a pH of greater than 4.
14. The method of claim 1 , wherein the acid generating fluid is a component of a fluid loss control pill.