Method of using sophorolipids or mannosylerythritol lipids as acid corrosion inhibitors in well treatment operations

1. A method of inhibiting corrosion during a well treatment operation which comprises introducing into a well a composition comprising a corrosion inhibitor of at least one sophorolipidic compound selected from the group consisting of:

or a mannosylerythritol lipid of the structural formula:

wherein R and R 1 are hydrogen or acetyl and n is from 6 to 10;

or a combination thereof.

2. The method of claim 1 , wherein the corrosion inhibitor is at least one of the sophorolipidic compounds of the structural formula (I) or (II).

3. The method of claim 2 , wherein (I) and (II) are in equilibrium with each other.

4. The method of claim 1 , wherein the corrosion inhibitor is the mannosylerythritol lipid of the structural formula (III).

5. The method of claim 1 , wherein the composition further comprises a corrosion inhibitor intensifier selected from the group consisting of formic acid, sodium formate, potassium formate, methylformate, ethylformate, iodide containing materials, metal oxides and combinations thereof.

6. The method of claim 5 , wherein the corrosion inhibitor intensifier is selected from the group consisting of potassium iodide, sodium iodide, copper iodide, molecular iodide and bismuth iodide.

7. The method of claim 1 , wherein the well treatment operation is a well stimulation process.

8. The method of claim 1 , wherein the corrosion inhibitor is a mixture of the sophorolipidic compounds of the structural formula (I) and (II).

9. A method of treating an alloy surface during a well treatment operation comprising the step of contacting the alloy surface with a treatment fluid comprising an aqueous acidic fluid and a corrosion inhibitor selected from the group consisting of at least one sophorolipidic compound of the structural formula:

and a mannosylerythritol lipid of the structural formula:

wherein R and R 1 are hydrogen or acetyl and n is from 6 to 10

or a combination thereof, wherein reduction in corrosion of the alloy surface is greater than when the alloy surface is only contacted with the aqueous acidic fluid.

10. The method of claim 9 , wherein the corrosion inhibitor is a mannosylerythritol lipid of the structural formula (III).

11. The method of claim 9 , wherein the corrosion inhibitor is at least one of the sophorolipidic compounds of structural formula (I) or (II).

12. The method of claim 9 , wherein the corrosion inhibitor is a mixture of the sophorolipidic compounds of the structural formula (I) and (II).

13. A method of inhibiting corrosion of a steel surface in contact with an acidic fluid during a well treatment operation comprising the steps of:

(a) contacting the acidic fluid with a corrosion inhibitor of at least one sophorolipidic compound selected from the group consisting of:

or a mannosylerythritol lipid of the formula:

wherein R and R 1 are hydrogen or acetyl and n is from 6 to 10;

or a combination thereof; and

(b) contacting the steel surface with the acidic fluid and the corrosion inhibitor.

14. The method of claim 13 , wherein the step of contacting the steel surface with the acidic fluid and the corrosion inhibitor comprises pickling a tubular, cleaning a wellbore, matrix acid stimulation, acid fracturing, acid tunneling, scale treatment, coiled tubing application, or damage removal.

15. A composition for use in the acid treatment of wells, comprising:

(a) a corrosion inhibitor selected from the group consisting of at least one sophorolipidic compound of the structural formula:

and a mannosylerythritol lipid of the structural formula:

or a combination thereof; and

(b) a corrosion inhibitor intensifier in an acidic solution.

16. The composition of claim 15 , wherein the acid of the acidic solution is selected from the group consisting of hydrochloric acid, hydrochloric-hydrofluoric acid, acetic acid, formic acid, citric acid, phosphonic acid, methane sulfonic acid and mixtures thereof.

17. The composition of claim 15 , wherein the corrosion inhibitor intensifier is selected from the group consisting of formic acid, sodium formate, potassium formate, methylformate, ethylformate, iodide containing materials, metal oxides, and combinations thereof.

18. The composition of claim 15 , wherein the corrosion inhibitor is a mannosylerythritol lipid of the structural formula (III).

19. The method of claim 15 , wherein the corrosion inhibitor is at least one of the sophorolipidic compounds of structural formula (I) or (II).