EMULSIFIED ACID COMPRISING WASTE OIL FOR ACIDIZING GEOLOGICAL FORMATIONS

• US 20180282614A1
• Filed: 03/01/2018
• Published: 10/04/2018
• Est. Priority Date: 04/03/2017
• Status: Active Grant

• Current Assignee: King Fahd University of Petroleum & Minerals (Government of Saudi Arabia)
• Original Assignee: King Fahd University of Petroleum & Minerals (Government of Saudi Arabia)
• Inventors: SULTAN, Abdullah S., SIDAOUI, Ziad
• Granted Patent: US 10,450,502 B2
• Time in Patent Office: Days
• CPC Class Codes: C09K 2208/32 Anticorrosion additives
• CPC Class Codes: C09K 8/70 characterised by their form or by the form of their components, e.g. foams
• CPC Class Codes: C09K 8/74 combined with additives added for specific purposes
• CPC Class Codes: E21B 43/27 by use of eroding chemicals, e.g. acids

Abstract

A method of acidizing a subterranean geological formation by injecting an emulsified acid into a wellbore, wherein the emulsified acid includes at least an aqueous phase comprising a hydrochloric acid solution, an oil phase comprising waste oil, and an emulsifier, and wherein the waste oil contains 45-75% by weight of aromatic compounds and preferably contains less than 0.5% by weight of non-hydrocarbon compounds. Various embodiments, and combinations of embodiments, of the emulsified acid and the method of acidizing are provided.

Claims

1. A method of acidizing a subterranean geological formation surrounding a wellbore, comprising:

injecting an emulsified acid into the wellbore to acidize the subterranean geological formation,

wherein the emulsified acid comprises

60-80% by volume of an aqueous phase comprising hydrochloric acid,

20-40% by volume of an oil phase comprising a waste oil, and

0.1-3.0% by volume of an emulsifier, relative to the total volume of the emulsified acid,

wherein the waste oil comprises 45-75% by weight of aromatic compounds, relative to the total weight of the waste oil, wherein the aromatic compounds are at least one selected from the group consisting of a monocyclic aromatic hydrocarbon, a polycyclic aromatic hydrocarbon, and a naphthene aromatic compound.

2. The method of claim 1, wherein the waste oil further comprises 20-25% by weight of aliphatic compounds, and 25-30% by weight of cycloaliphatic compounds, relative to the total weight of the waste oil.

3. The method of claim 1, wherein the waste oil does not include a non-hydrocarbon compound selected from the group consisting of a sulfur compound, a nitrogen compound, an oxygen compound, and asphaltene.

4. The method of claim 1,

wherein the waste oil further comprises up to 0.5% by weight of at least one non-hydrocarbon compound, relative to the total weight of the waste oil, and

wherein the at least one non-hydrocarbon compound is selected from the group consisting of a sulfur compound, a nitrogen compound, an oxygen compound, and asphaltene.

5. The method of claim 1, wherein the emulsified acid has an apparent viscosity of 500 to 10,000 cP at a temperature of 20 to 100°

C.

6. The method of claim 1, wherein the emulsified acid is injected into the wellbore for up to 6 hours in a continuous fashion.

7. The method of claim 1, wherein the emulsified acid contains droplets with an average diameter of 1.0 to 2.5 μ

m.

8. The method of claim 1, wherein the emulsified acid comprises 0.5-1.5% by volume of the emulsifier, relative to the total volume of the emulsified acid.

9. The method of claim 1, wherein the hydrochloric acid is present in the aqueous phase at a concentration of 5-30% by weight, relative to the total weight of the aqueous phase.

10. The method of claim 1, wherein the aqueous phase further comprises at least one mineral acid selected from the group consisting of nitric acid, sulfuric acid, phosphoric acid, perchloric acid, hydrofluoric acid, hydrobromic acid, hydroiodic acid, and boric acid.

11. The method of claim 1, wherein the emulsifier is at least one selected from the group consisting of an ethoxylated glycol, an ethoxylated phenol, a propoxylated glycol, and a propoxylated phenol.

12. The method of claim 1, wherein the emulsified acid further comprises 0.1-0.5% by volume of a corrosion inhibitor, relative to the total volume of the emulsified acid.

13. The method of claim 12, wherein the emulsified acid contains droplets with an average diameter of 2.5 to 4.0 μ

m.

14. A method of drilling a subterranean geological formation, comprising:

drilling the subterranean geological formation to form a wellbore therein; and

circulating an emulsified acid in the wellbore,

wherein the emulsified acid comprises

60-80% by volume of an aqueous phase comprising a hydrochloric acid solution,

20-40% by volume of an oil phase comprising waste oil, and

0.1-3.0% by volume of an emulsifier, relative to the total volume of the emulsified acid,

wherein the waste oil comprises 45-75% by weight of aromatic compounds, relative to the total weight of the waste oil, wherein the aromatic compounds are at least one selected from the group consisting of a monocyclic aromatic hydrocarbon, a polycyclic aromatic hydrocarbon, and a naphthene aromatic compound.

15. The method of claim 14, wherein the waste oil does not include a non-hydrocarbon compound selected from the group consisting of a sulfur compound, a nitrogen compound, an oxygen compound, and asphaltene.

16. The method of claim 14, wherein the emulsified acid is circulated for up to 6 hours.

17. A method of forming an emulsified acid, comprising:

mixing a first mixture comprising waste oil and an emulsifier with a second mixture comprising a hydrochloric acid solution and stirring, thereby forming the emulsified acid,

wherein a volume ratio of the emulsifier to the waste oil in the first mixture is 1;

400 to 1;

10,

wherein the waste oil comprises 45-75% by weight of aromatic compounds, relative to the total weight of the waste oil, and

wherein the second mixture is mixed with the first mixture in a drop-wise fashion at a mixing rate of 0.5 mL/min to 1.5 mL/min.

18. The method of claim 17, wherein the waste oil does not include a non-hydrocarbon compound selected from the group consisting of a sulfur compound, a nitrogen compound, an oxygen compound, and asphaltene.

19. The method of claim 17,

wherein the second mixture further comprises a corrosion inhibitor, and

wherein a volume ratio of the corrosion inhibitor to the hydrochloric acid solution in the second mixture is 1:

1,000 to 1;

100.

20. The method of claim 17, wherein the waste oil further comprises up to 0.5% by weight of non-hydrocarbon compounds, relative to the total weight of the waste oil, the method further comprising:

passing the waste oil through a filter with a mesh size of up to 0.5 μ

m, and

separating at least a portion of the non-hydrocarbon compounds from the waste oil before the mixing.