Method of manipulating hydrophilicity and hydrophobicity of conventional dye molecules for tracer applications

A method of making a functionalized fluorescent dye, comprising:

• dissolving a water-soluble isothiocyanate-containing fluorescent dye in an aqueous solvent to yield an aqueous dye solution, wherein the water-soluble isothiocyanate-containing fluorescent dye is selected from the group consisting of fluorescein isothiocyanate, Rhodamine B isothiocyanate, or tetramethylrhodamine isothiocyanate, or any isoform thereof;
• dissolving a functional group comprising a primary amine in an organic solvent to yield an organic functional group solution, wherein the functional group comprising a primary amine is selected from Group I, Group II, or Group III, wherein
• Group I consists of ethylamine, propylamine, isopropylamine, butylamine, tert-butylamine, hexylamine, octylamine, decylamine, dodecylamine, tetradecylamine, and hexadecylamine,
• Group II consists of aniline, benzylamine, phenethylamine, 3-phenyl-1-propylamine, 4-phenylbutylamine, and 6-phenylhexan-1-amine, and
• Group III consists of 4-fluoroaniline, 3,4-difluoroaniline, 2,4,6-trifluoroaniline, 4-(trifluoromethyl)aniline, 3,5-bis(trifluoromethyl)aniline, 2,4,6-tris(trifluoromethyl)aniline, 4-fluoro-3-(trifluoromethyl)aniline, 4-(trifluoromethoxy)aniline, 4-fluorobenzylamine, 2,4-difluorobenzylamine, 2,3,4-trifluorobenzylamine, 3-(trifluoromethyl)benzylamine, and 3,5-bis(trifluoromethyl)benzylamine;
• forming an emulsion of the aqueous dye solution and the organic functional group solution;
• and
• extracting the functionalized fluorescent dye from the organic functional group solution, wherein the functionalized fluorescent dye is a reaction product of the water-soluble isothiocyanate-containing dye and the functional group comprising a primary amine.

A method of tracing fluid flow in a subterranean formation, comprising:

• mixing a functionalized fluorescent tracer into a fluid to yield a tracer fluid, wherein the functionalized fluorescent tracer comprises an isothiocyanate-containing fluorescent dye functionalized with a functional group comprising a primary amine, wherein
• the isothiocyanate-containing fluorescent dye is selected from the group consisting of fluorescein isothiocyanate, Rhodamine B isothiocyanate, or tetramethylrhodamine isothiocyanate, or any isoform thereof,
• the functional group comprising a primary amine is selected from Group I, Group II, or Group III, wherein
• Group I consists of ethylamine, propylamine, isopropylamine, butylamine, tert-butylamine, hexylamine, octylamine, decylamine, dodecylamine, tetradecylamine, hexadecylamine, and octadecylamine,
• Group II consists of aniline, benzylamine, phenethylamine, 3-phenyl-1-propylamine, 4-phenylbutlamine, and 6-phenylhexan-1-amine, and
• Group III consists of 4-fluoroaniline, 3,4-difluoroaniline, 2,4,6-trifluoroaniline, 4-(trifluoromethyl)aniline, 3,5-bis(trifluoromethyl)aniline, 2,4,6-tris(trifluoromethyl)aniline, 4-fluoro-3-(trifluoromethyl)aniline, 4-(trifluoromethoxy)aniline, 4-fluorobenzylamine, 2,4-difluorobenzylamine, 2,3,4-trifluorobenzylamine, 3-(trifluoromethyl)benzylamine, and 3,5-bis(trifluoromethyl)benzylamine;
• flowing the tracer fluid into a first subterranean formation;
• recovering a sample from the first subterranean formation or a second subterranean formation;
• analyzing the sample for a fluorescent signal;
• and
• further separating the sample and analyzing the sample for a barcode functional group.