Four-dimensional fluorescence imaging of oil generation: development of a new fluorescence imaging technique

Abstract

This paper presents the development of a new fluorescence imaging technique, for visualization of the complex array of fluorescence spectral data and of progressive petroleum generation. The different rate of fluorescence spectral evolution of marine algaal kerogen corresponds with distinct differences in kinetics of petroleum generation. The differential red-shifting of the spectra obtained from different particles in the same sample reflects the differential thermal alteration controlled by the initial distribution of particles with different thermal stability. The particle-specific chemical variabilities are captured by fluorescence spectral data, which are represented as surfaces, containing information regarding relative intensities, wavelengths, and principal component (PC1) projections of the raw spectral data. Continuous functions that describe fluorescence surfaces were derived by polynomial trend surface analysis to define a Fluorescence Imaging Maturity Index (FIMI). FIMI and PGI (Petroleum Generation Index), determined by mass balance calculations of the carbon budget in the natural source rock systems, are used in regression analysis to establish a function for predicting PGI (≈transformation ratio). The stacking of fluorescence surfaces according to depth of burial (from a given formation across a basin, or from different formations in the same well), provides 4-dimensional visualization of the dynamics of progressive oil generation.