A composition includes a functionalized fluorescent dye. The functionalized fluorescent dye includes an isothiocyanate-containing dye that is functionalized with a functional group. The functional group includes a primary amine. The functionalized fluorescent dye can be mixed with a fluid to form a tracer fluid for tracing fluid flow in a subterranean formation.

A composition includes a functionalized fluorescent dye. The functionalized fluorescent dye includes an isothiocyanate-containing dye that is functionalized with a functional group. The functional group includes a primary amine. The functionalized fluorescent dye can be mixed with a fluid to form a tracer fluid for tracing fluid flow in a subterranean formation.

A composition includes a functionalized fluorescent dye. The functionalized fluorescent dye includes an isothiocyanate-containing dye that is functionalized with a functional group. The functional group includes a primary amine. The functionalized fluorescent dye can be mixed with a fluid to form a tracer fluid for tracing fluid flow in a subterranean formation.

An organic colorant complex with the following general structure:

AB.sub.n(DE).sub.mT.sub.xQ.sub.y

wherein A is an organic chromophore; B is an electrophilic reactive group covalently bonded to A directly or through a linking group; D is a nucleophilic linking group covalently bonding B and E, selected from the group consisting of NR, O, S, and 4-oxyanilino (—HN-Ph-O—); wherein R is selected from the group consisting of H, alkyl, aryl, and E; E is an organic alkyl and aryl group or an end group; T is an ionic group covalently linked to A; Q is an organic cation, bonded to the organic chromophore A through ionic interaction with T; n, m, x, and y are independent integers from 1 to 10.

An organic colorant complex with the following general structure:

AB.sub.n(DE).sub.mT.sub.xQ.sub.y

wherein A is an organic chromophore; B is an electrophilic reactive group covalently bonded to A directly or through a linking group; D is a nucleophilic linking group covalently bonding B and E, selected from the group consisting of NR, O, S, and 4-oxyanilino (HN-Ph-O); wherein R is selected from the group consisting of H, alkyl, aryl, and E; E is an organic alkyl and aryl group or an end group; T is an ionic group covalently linked to A; Q is an organic cation, bonded to the organic chromophore A through ionic interaction with T; n, m, x, and y are independent integers from 1 to 10.

The invention relates to block copolymer comprising i) A first block wherein at least 65 mol-% of the repeating units of the first block are repeating units of the formula (I)[CH.sub.2CH.sub.2O], ii) A second block wherein at least 90 mol-% of the repeating units of the second block are repeating units of at least one of formulae (II) or (III), wherein the groups R.sup.1, R.sup.2, and R.sup.3 independent of each occurrence are selected from hydrocarbyl groups having 1 to 40 carbon atoms, which are optionally substituted by ether or hydroxyl groups, and wherein the groups R.sup.1 and R.sup.2 are optionally linked to each other such that a nitrogen heterocyclic structure is present, iii) A third block which is different from the first block and the second block and which is more hydrophobic than the first block. ##STR00001##

A composition includes a functionalized fluorescent dye. The functionalized fluorescent dye includes an isothiocyanate-containing dye that is functionalized with a functional group. The functional group includes a primary amine. The functionalized fluorescent dye can be mixed with a fluid to form a tracer fluid for tracing fluid flow in a subterranean formation.