Modified acid compositions as alternatives to conventional acids in the oil and gas industry
An aqueous modified acid composition for use in oil industry activities, said composition comprising: an amino acid, an alkanolamine and strong acid wherein the mineral acid:alkanolamine/amino acid are present in a molar ratio of not more than 15:1, preferably not more than 10:1; it can also further comprise a metal iodide or iodate. Said composition demonstrates advantages over known conventional acids and modified acids.
1. An aqueous modified acid composition comprising:
a mineral acid;
an amino acid; and
an alkanolamine;
wherein the mineral acid:alkanolamine/amino acid are present in a molar ratio ranging from 3:1 to 12:1.
2. An aqueous modified acid composition according to claim 1 , wherein the amino acid:alkanolamine proportion ranges from 1%: 99% to 99%: 1%.
3. An aqueous modified acid composition according to claim 1 , wherein the amino acid:alkanolamine proportion ranges from 20%: 80% to 80%: 20%.
4. An aqueous modified acid composition according to claim 1 , wherein the amino acid:alkanolamine proportion ranges from 30%: 70% to 70%: 30%.
5. An aqueous modified acid composition according to claim 1 , wherein the amino acid:alkanolamine proportion is 50%: 50%.
6. The aqueous modified acid composition according to claim 1 , wherein the mineral acid:alkanolamine/amino acid are present in a molar ratio of not more than 10:1.
7. The aqueous modified acid composition according to claim 1 , wherein the mineral acid:alkanolamine/amino acid are present in a molar ratio of not more than 7.0:1.
8. The aqueous modified acid composition according to claim 1 , wherein the mineral acid:alkanolamine/amino acid are present in a molar ratio of not more than 4:1.
9. The aqueous modified acid composition according to claim 1 , wherein the mineral acid:alkanolamine/amino acid are present in a molar ratio of not more than 3:1.
10. The aqueous modified acid composition according to claim 1 , wherein the mineral acid:alkanolamine/amino acid are present in a molar ratio ranging from 5:1 to 10:1.
11. The aqueous modified acid composition according to claim 1 , wherein the alkanolamine is selected from the group consisting of: monoethanolamine; diethanolamine; triethanolamine and combinations thereof.
12. The aqueous modified acid composition according to claim 1 , wherein the amino acid is selected from the group consisting of: lysine, glycine, valine, arginine, histidine, threonine, methionine and combinations thereof.
13. The aqueous modified acid composition according to claim 1 , wherein the alkanolamine is monoethanolamine.
14. The aqueous modified acid composition according to claim 1 , wherein the alkanolamine is diethanolamine.
15. The aqueous modified acid composition according to claim 1 , wherein the mineral acid is selected from the group consisting of: HCl, nitric acid, sulfuric acid, sulfonic acid, phosphoric acid, and combinations thereof.
16. The aqueous modified acid composition according to claim 1 , further comprising a metal iodide or iodate selected from the group consisting of: cuprous iodide; potassium iodide; sodium iodide; lithium iodide and combinations thereof.
17. The aqueous modified acid composition according to claim 1 , further comprising an alkynyl alcohol or derivative thereof present in a concentration ranging from 0.01 to 5% w/w.
18. The aqueous modified acid composition according to claim 17 , wherein the alkynyl alcohol or derivative thereof is propargyl alcohol or a derivative thereof.
19. The aqueous modified acid composition according to claim 16 , wherein the metal iodide is present in a concentration ranging from 0.1 to 2% by weight of the total weight of the composition.
20. The use of an aqueous modified acid composition in an oil industry activity, said composition comprising:
a mineral acid;
an amino acid; and
an alkanolamine;
wherein the mineral acid:alkanolamine/amino acid are present in a molar ratio ranging from 3:1 to 12:1, and wherein the use comprises an activity selected from the group consisting of: stimulate formations; assist in reducing breakdown pressures during downhole pumping operations; treat wellbore filter cake post drilling operations; assist in freeing stuck pipe; descale pipelines and/or production wells; increase injectivity of injection wells; lower the pH of a fluid; remove undesirable scale on a surface selected from the group consisting of: equipment, wells and related equipment and facilities; fracture wells; complete matrix stimulations; conduct annular and bullhead squeezes & soaks; pickle tubing, pipe and/or coiled tubing; increase effective permeability of formations; reduce or remove wellbore damage; clean perforations; and solubilize limestone, dolomite, calcite and combinations thereof.
21. Method of treating a metal surface with a composition comprising:
a mineral acid;
an amino acid; and
an alkanolamine;
wherein the mineral acid:alkanolamine/amino acid are present in a molar ratio ranging from 3:1 to 12:1: said method comprising the steps of:
providing said composition;
exposing said metal surface to said composition;
allowing said composition a sufficient period of time to act upon said surface; and
optionally, removing the acid composition when the exposure time has been determined to be sufficient for the operation to be complete or sufficiently complete.