SHORTWAVE INFRARED HYPERSPECTRAL IMAGING: A NOVEL METHOD FOR ENHANCING THE VISIBILITY OF SEDIMENTARY AND BIOGENIC FEATURES IN OIL-SATURATED CORE

A common challenge of logging core from heavy-oil reservoirs is that sedimentary and biogenic features are difficult to see in fine-grained, well-sorted, and oil-saturated strata. In this study, hyperspectral imaging is shown to be an effective method for enhancing the visibility of sedimentary fabric and trace fossils in oil-saturated core. Shortwave infrared (SWIR) hyperspectral imagery of Lower Cretaceous McMurray Formation oil-sands core from northeastern Alberta, Canada, was investigated at various wavelengths and resolutions. Color composite imagery consisting of wavelength bands at 2162, 2199, and 2349 nm in the red, green, and blue channels, respectively, dramatically enhanced the clarity of sedimentary features in structureless-appearing oil sand. In many cases, spectral imagery revealed features that are completely invisible to the unaided eye. In coarser-grained sections (fine to coarse sand), the enhanced contrast of sedimentological features is attributed predominantly to variability in grain size and bitumen saturation. In finer-grained sections (very fine to fine sand), enhanced contrast is mainly ascribed to variability in relative abundance of clays. A spatial resolution of at least 0.25 mm/pixel is required for imaging trace fossils, while lower resolutions (1.2-1.5 mm/pixel) are sufficient for enhancing the visibility of most sedimentary structures.