Citric acid based emulsifiers for oilfield applications exhibiting low fluorescence
View Patent ↗The present invention relates to a composition of citric acid based emulsifiers comprising polyamides for oilfield drilling applications that exhibit very low fluorescence, and to a process for their preparation.
1. A process for the preparation of a triamide having low fluorescence which comprises reacting a monofunctional acid with a polyamine in order to form an amide; heating said amide for a time and at a temperature effective to form the imidazoline of said amide; and reacting said imidazoline of said amide with citric acid in order to form a triamide product having a fluorescence value of less than about 400.
2. The process of claim 1 wherein said monofunctional acid is a C 12 -C 22 fatty acid of the formula:
R 1 —COOH,
wherein, R 1 is a C 11 -C 21 alkyl group; a salt a C 12 -C 22 fatty acid of the formula:
R 1 —COO − M + ,
wherein, M+ is an alkali metal ion and R 1 is a C 11 -C 21 alkyl group, an anionic derivative of a C 12 -C 22 fatty acid of the formula
R 1 —COO − ,
wherein, R 1 is a C 11 -C 21 alkyl group, or mixtures thereof.
3. The process of claim 1 wherein said polyamines are represented by the formula:
wherein each R is independently selected from H, an alkyl group, an aromatic group, and combinations thereof and x is an integer.
4. The process of claim 3 wherein said polyamine is diethylenetriamine.
5. The process of claim 1 wherein said triamide has a fluorescence value of less than about 300.
6. The process of claim 1 wherein said effective temperature for imidazoline formation is equal to or greater than 177° C.
7. The process of claim 6 wherein said effective temperature for imidazoline formation is equal to or greater than 204° C.
8. The process of claim 1 wherein said imidazoline of said amide is reacted with said citric acid at a temperature of from about 149-177° C. in order to form a polyamide product having low fluorescence.
9. An emulsifier composition which comprises at least one polyamide, wherein said polyamide comprises at least one compound of general formula (I) and (II):
wherein R is a saturated or unsaturated, straight or branched chain fatty acid, and R′ is citric acid, and wherein said composition has a fluorescence value of less than about 400.
10. The composition of claim 6 wherein said composition has a fluorescence value of less than about 300.
11. A drilling fluid composition which comprises the emulsifier composition of claim 6 .
12. The composition of claim 10 wherein said composition has a fluorescence value of less than about 200.
13. The process of claim 1 wherein said triamide has a fluorescence value of less than about 200.