Method for tracing subterranean formations with oil-soluble organic molecular tracers and extracting them of from oil phases

Abstract

Functionalized fluorescent tracers, compositions, and methods for extracting the functionalized fluorescent tracers from oil phases and other wellbore or drilling fluids are provided. In some implementations, a sorbent for extracting tracer molecules from a fluid includes a silica-based sorbent. The silica-based sorbent includes a hydrophobic functional group and an ionic functional group. In some implementations, the ionic functional group is positively charged. In some implementations, the ionic functional group is negatively charged. A method of extracting a functionalized dye from an oil phase includes mixing a sorbent for extracting tracer molecules with an oil phase sample that includes a functionalized fluorescent tracer, recovering the sorbent from the oil phase, and dispersing the sorbent in an organic solvent. In some implementations, the method includes lowering the pH of the organic solvent. In some implementations, the method includes raising the pH of the organic solvent.

Dependencies are inferred from the claim text.