Systems, methods and apparatus for analysis of reservoir fluids using surface plasmon resonance

An optical sensor comprising:

• a flow cell that is configured to permit flow of a hydrocarbon-based analyte through the flow cell;
• a metallic film disposed adjacent or within the flow cell;
• a light source configured to generate polychromatic light;
• at least one optical element configured to direct polychromatic light produced by the light source for supply to an interface of the metallic film under conditions of surface plasmon resonance and to direct polychromatic light reflected at the interface of the metallic film for output from the at least one optical element, wherein the polychromatic light reflected at the interface of the metallic film is sensitive to surface plasmon resonance at the interface of the metallic film in order to provide an SPR sensing region within the flow cell;
• at least one spectrometer operably coupled to the at least one optical element, wherein the at least one spectrometer is configured to measure spectral data of polychromatic light reflected at the interface of the metallic film as output by the least one optical element;
• and
• a computer processing system operably coupled to the at least one spectrometer, wherein the computer processing system is configured to process the spectral data measured by the at least one spectrometer over time as the hydrocarbon-based analyte flows through the flow cell to determine SPR peak wavelength over time, and wherein the computer processing system processes the SPR peak wavelength over time to determine at least one property related to phase transition of the hydrocarbon-based analyte.